*I think you're maybe reading more into what a forum is than is real.
This isn't a group of people chatting, and someone trying to join the convo. It's simply a bunch of posts. If you Post something someone agrees with, or disagrees with or finds interesting they will comment on it. If you post something that catches no ones interest they don't.
It's all about rhe post. It's not about the person. It's not a group of friends.*
I agree with this now but would have utterly disagreed 10 years ago. Or even 2 years ago.
There was a huge tendency for posters who knew each other on a thread to engage in mutual backslapping, often to the exclusion of others.....even the OP.
Even now, people fangirl WorraLiberty, Anyfucker and Sparklingbrook. All of whom are lovely posters with wise words who add a lot to MN. But people do tend to respond to their posts and not earlier posters who may have made the exact same point.
I don't think there are cliques now. Just people who desperately want recognisable posters to acknowledge them, as some weird validation.