[warning: rant coming]
We all have the capacity to reply to any thread as we choose. Sometimes the replies stir up a bit of dust. That's fine; that's expected.
But there are times when a reply to a thread does nothing to return the thread to the original topic. The reply does nothing to meaningfully stimulate polite (or at least amicable) actions between members. There are times when the reply is meant to do nothing but incite some sort of fury.
Even if a reply is not meant to incite fury, it is absolutely necessary to think about what might happen. Who might reply. How they might reply. And you have to be prepared to reply with a level head and with a level of decorum that makes you, the user, look good.
At the same time, we must make sure that our replies make the site a welcoming environment for the people who love to come here as much as I know we all do!
So there is rarely a problem of free speech, at least on this site; no, no, the problem is the environment that we see being created. An environment that is acidic in any way, shape, form or fashion is not of our desire. An environment where we cannot expect to have rational discussion is not of our desire. More importantly, we can see that the majority of the members do not desire a negative environment.
But y'know, I think there is something that could help out: making use of private messages: I don't know how often people use private messages. There could be quite a few meaningful conversations going on behind the scenes and the rest of us would never know any differently. I personally encourage the use of private messages; that way, you can ask someone "Hey, what was your thought process when you wrote this? I want to understand you better." ...To be honest, an attempt to understand others should be paramount no matter how you converse with them, but a private message will allow you to deal one-on-one with a person and makes it easier to separate what you want to say from what others are saying. This way, there might be fewer miscommunications.
But what do I know? I'm only one person, and this is only my opinion. But I think we can all get along around here much better if we work on communicating better. Until we communicate better, no amount of extra forums/subforums/private messages/areas of restricted access will make things better, because the problem will still exist.