2Pet 1:20 (NKJ) Knowing this first, that no prophecy of Scripture is of any private interpretation.This "private interpretation" prohibition cuts both ways. In other words, it is no good for everyone to come up with their own unique private interpretation divorced from what a text is really saying--as if scripture were malleable to our opinions. But on the other hand, some texts are veiled or obtuse, and neither should a person assert a dogmatic private interpretation where reasonable people might disagree.
Certainly some verses are open to multiple interpretations. Symbolic texts especially fall into this category, but also factual texts as well.
For example, "Jesus wept": but why? Was it over the unbelief all around? That His friend was "by now stinking"? Over human death? We are not told why He wept, only that He did. I have an idea, but I would not assert it was "the right answer", as how could I be sure? Thus, if someone suggests something other than the conclusion I have drawn, I will listen and learn. If the meeting format is such to allow it, I might assert my own commentary if I thought it might be edifying. By the way, I think He wept because human death sucks, and He was a human.
But with other texts your dogmatic friend may be right, at least in the principal meaning. There might be "rhema" (actually "logos") applications that the Spirit might quicken as well, using Scripture as a sort of grist, but this does not take away from the clear, principal meaning.
For example, if someone says that in the Kingdom Parables: "The field is the church, and the seed is the good works that we do for those in the world", we can sharply and forcefully state that this is wrong and in error. There is no room for such larks of personal interpretation, as Jesus told us that: "The field is the world, and the seed is the Gospel message". Again, if Scripture says: "Do not commit adultery", and someone comes up with some novel way to wiggle out of this, I do not consider this "Christian discussion", but a wolf being tolerated among us. (Jude 1:4)
My experience, unfortunately, among most small groups is that you get more liberality than is edifying in letting people "air" their false doctrines and interpretations. This is part of the lost art of doing church God's way, and we need to relearn it by the wind of the Spirit. While it is tolerable to let people say dumb, silly, or even demonic things if in ignorance or when they are young in the faith, what of the participant that is a secret Jehovah's Witness or Mormon constantly asserting "What this really means is..." And these stark examples are only offered to crisply delineate the problem of people spouting error and grieving the Spirit of truth. In general, the group must deal with this, especially the elders. For the church is a place of freedom, but not freedom for demons or the flesh. Thus, we need to forcefully repudiate scripture twisting for the sake of promoting false doctrine when it comes up. For occasionally what gets floated as an "interpretation" is really a false teaching, even a classic heresy. Satan loves to "tweak" believers meetings and to derail Christian lives with things like this. Ever heard of "doctrines of demons"?
In the west, we are slaves to "the question", which if asked can commandeer a meeting and "must be answered" in our culture. But consider how often Jesus answered questions or took them as genuine. Very seldom, in fact, even from His own disciples. If we aim to be "like Christ", then we might sort of aim at His ratio, eh? We might answer some questions, but others we will "see through" and so forth and either ignore or rebuke in response.
This is the warrior's work in the Kingdom of God. For we must strike a balance allowing genuine questions and ideas, but also quashing demonic doctrine (even from the sincerely wrong). This is what is meant by the violent image of spiritual warfare in correct context:
2 Cor 10:3-6 (NIV) For though we live in the world, we do not wage war as the world does. The weapons we fight with are not the weapon's of the world. On the contrary, they have divine power to demolish strongholds. We demolish arguments and every pretension that sets itself up against the knowledge of God, and we take captive every thought to make it obedient to Christ.This is part of the "good fight" that Paul was so passionate about.
Acts 20:29-31 (NIV) I know that after I leave, savage wolves will come in among you and will not spare the flock. Even from your own number men will arise and distort the truth in order to draw away disciples after them. So be on your guard! Remember that for three years I never stopped warning each of you night and day with tears.For many texts, we grieve the Spirit with larks of "interpretation". Often what is asserted flies in the face of the plain-sense meaning. It is a simple twisting of scripture, and the devil gives the groups that indulge such a pleasurable sense of "open mindedness". But an open mind is a cesspool of thought, and leads to disease. Rather, we "take every thought captive". We must have steel trap minds, the very mind of Christ.
With other scriptures we would do well not to assert more than the text will bear, as a multiplicity of interpretations and/or meanings can reasonably be held in view. Thus, we need an environment of freedom that comes from the violence of "demolishing arguments" and "every pretension that sets itself up against the knowledge of God". This is the nature of the spiritual war, especially when believers gather.
As for the freedom/violence conundrum, freedom only comes from nailing flesh on the cross. In a group, this can be socially painful, but nonetheless must be done or flesh will increase and Christ will decrease among us. We get life through death, and many ideas--even from a sweet old lady--are deserving of a swift sword-swipe decapitation by the word of God. Dispensing this "ministry" publicly and openly is instructive to all of us about what we all must do daily--nearly every moment. Consider these verses along this line.
Gal 5:13 (NIV) You, my brothers, were called to be free. But do not use your freedom to indulge the sinful nature...Thus, while I might submit a weird meditation to someone sound in the faith (or vice versa) that I suspect might be "off", I would never do this in a public meeting because if it is wrong it might derail someone's faith. Something about a millstone... (Mk 9:42). Others are not so circumspect, and if allowed to say "I think this means" or "What about?" will grieve the Spirit and maul the flock. What to do?
1Co 8:9 (NIV) Be careful, however, that the exercise of your freedom does not become a stumbling block to the weak.
1 Tim 1:3 (NIV) ...command certain men not to teach false doctrines any longer.This seems clear enough, eh? We may not like it, but we have been given our battle commands. Doctrine is crucially important to God, and thus we ought to take it seriously as well.
Titus 1:11 (NIV) They must be silenced, because they are ruining whole households by teaching things they ought not to teach.
As you can see, those who want to please men can "in NO WAY serve Christ", as Paul put it in Gal 1:10 and 1Th 2:4. We must die to our own desire to make everyone happy, for that is how false prophets operate. Rather we must seek to please God, and He calls us to offer up condemned flesh on the alter and let it fry.
In the case you mention, it may be more of just one person being dogmatic and speaking out of pride--as if he alone is the ultimate seer of scripture. Real teachers teach with "patience and careful instruction". You make a nice example of this, as you check things out and bounce ideas off of people in private before foisting them on others, and you are doing the noble work of "inventory" on your own ideas: taking each captive and seeing if it passes muster before Christ. If this person can back up what he is saying, and such is edifying to understand, then he might be gifted with knowledge or understanding. If not, then he is just "puffed up" with knowledge and "must be silenced".
1 Cor 14:40 (NIV) Everything should be done in a fitting and orderly way.As a concluding comment, a brother in our home church asked me recently about a teacher on the internet who was bringing an "ultimate reconciliation" message. Now my friend was flirting a bit on the fringes of universalistic ideas, so I checked it out at his request. As it turns out, Mr. "ultimate reconciliation" was a disguised universalist. When I pointed this out, my friend and I had a good talk on why universalism was a dangerous heresy. But I had a much more terse dialog with Mr. Universalism. Now consider these two men by way of example. One has an honest question based on interest or temptation, and is immature in the faith in a regard. What purpose would a "sharp rebuke" achieve? Rather, a kind answer with patient instruction is appropriate. But what of our heretic? He knows that Christians in general would not give him the time of day if he were to teach universalism, so he has repackaged it and hopes to gain entrance. This is a deliberate deception on his part. It is a sheepskin worn by a self-aware wolf. What purpose would a "kind answer" achieve with this man? Rather, a strong rebuke is in order. We should not be treating wolves like sheep, nor sheep like enemies. But we must be soberminded that both are among us, and more wolves than we would like to admit.
Titus 1:13 (KJV) This witness is true. Wherefore rebuke them sharply, that they may be sound in the faith.