Diversity of opinions isn't automatically good for its own sake. I'm sure with a little imagination, you can come up with all sorts of objectively stupid opinions. Are those what you want to sift through? If you have a space where you allow all opinions no matter what, you'll end up overwhelmed by the stupidest ones. If you moderate at all, you will always be accused of bias by someone. If you doubt any of this, just start hosting your own server!

tl;dr: different places have different vibes. That's OK. Not everywhere has to contain all opinions.