To me it's pretty simple; not everyone's playstyle is everyone else's favorite. Some of us like and prioritize some things (combat, mystery and horror, romantic/sexual tropes, writing styles and responsiveness, etc) different than others do.
In fact we've discussed most of those in great length in other threads right here.
As such we'll indeed go and find some fun playing with those whose strengths are in the same areas we enjoy. There's nothing wrong with any of this as long as we also don't go out of our way to be assholes to folks who just like different playing styles.
You'd think that's a low bar but it's not. How many times have we seen someone complain here that other people are locked in rooms together, heavily implying they are having teh tee-es, and being annoyed about it? How many times have we seen others shit all over a canon character out of entitlement? How dare they play Batgirl as a happy-go-lucky crime-fighter instead of a brooding uber-hacker? It's ruining everything!
It's a big hobby. Many different interpretations of fun fit within it, and maybe we just need to back off others, stop worrying as much about what entertains them and concern ourselves with our own sense of enjoyment.