You’re right in a way, but I think you’re applying a narrow definition of “opinion” when I think most people ITT are thinking about “behaviours”.
Sure, it’s not great to exclude dissenting political opinions, the intolerance paradox being a notable exception. That said, I’m not here to discuss politics.
Say for example that some users will do anything for fake internet points - post anything, say anything, there behaviour is guided by the pursuit of karma and building some kind of following. Other users will do anything for engagement, whatever it takes to get others to engage with them including trolling. I’m happy enough for these types of users to find more rewarding platforms elsewhere. Note that’s different to excluding them, it’s just being a part of a place that isn’t fertile ground for their fixations.