A school of fish. They swim together like a flock of birds.
It’s not just religions, or ethnicities, or tribes, it’s ideologies. It’s social cliques, sexualities, corporations. People like to be in a group, they like to blend in, and represent that group, and defend it, and identify with and as it.
This seems to be political, but it’s not. It’s just a mentality. As the old saying goes, either you are in, or you are out.
Perhaps that’s what philosophy appeals to, or who it appeals to. The un-tribed, the outcast. The random free thinker.
But even as we do this, we are grouping ourselves informally—we like philosophy.

People like to be in a group? Well you make too many assumptions, I prefer a small group of friends, loosely around a half dozen or so.
I ain’t got time or memory to keep up with the drama of 100+ people.
Each of your friends will have six friends, and each of them will have six friends, etc.
Or maybe you’re in a cult, which is interesting.
That web, or branching out, forms a psychic linking, which creates a much larger group than you’re aware that you’re involved with.
Just being involved in a clique doesn’t mean that clique isn’t part of a broader ideological set, which is likely involved in a much larger group mind, in which you involuntarily participate.