I also think cultural background, education, age and our own perception of "professional conduct" play a very important role in how we engage with other colleagues online.
Since people are very different, it's very difficult to create a massive community where everyone is happy. I think it is only possible if community revolves around 1 single goal and 1 point of discussion that unites community as a whole.
But even with 1 single goal you'll still have clashing opinions every know and then ?
I think they key is finding a small group of people who you like and whose values you share and sticking to this group of people. So my advice would be to choose a micro-community over a macro-community if you want to feel more free and relaxed. At least, you'll know what to expect from people because you know them very well.
When you try to defend your opinion in a large group of strangers, things can turn into Wild Wild West pretty quickly.