I think I understand the point you're making. I spent several months reading here before I ever posted anything, and many months later I'm still not a frequent poster. I love it here, in part because of the challenges (which I think are what you are alluding to in your post).
It's a tough board, in that anything said well be read critically to see if it holds up under careful examination. There's little patience for theists who arrive intent on saving us godless sinners, but can't be bothered to spend some time reviewing the history to see if they have anything new to add. There's little tolerance for assertions that aren't, or can't be, supported by evidence, ideally empirical evidence. No one gets away with BS on the "serious" topics, and may be called out for it on more light topics too. Many of the members have been here for a long time, and are often well read across a wide range of topics, so odds are good there's someone in the community who is fairly knowledgeable in whatever topic may be under discussion. And everyone knows how to use Google.
It's all about critical thinking. Part of what I love about this place is that I can see a well-constructed argument in action. I can see logical fallacies in "real world" context, and watch them get dismantled. Sometimes the conversation takes a familiar path, and sometimes it deviates into completely unexpected areas, but it's almost always enlightening. You can get hammered on for a poor word choice. You will hear about it if you post without thinking through what your audience is going to read in your words that you may not have intended. Any bias that shows up will be brought into the light to be examined in minute detail. And you'll be a better communicator for it.
I'm not all that great with biblical arguments, but get lots of useful information from members who are. I learn all kinds of stuff about politics that I might not otherwise find. I get exposed to views that may not mesh with my own, but are presented in a way that at least makes me have to consider if my views are valid, or habitual. Most of that gets processed in my head, not on the pages.
In general, I find the tone tends to be fairly serious. Get involved in conversations that aren't "heavy" and get familiar with the areas that don't tend to spark as much conflict. As long as you are prepared to substantiate whatever you say here, you'll be fine. I strongly recommend easing into this place as opposed to a headlong dive into the deep end.
Edited for spelling error.