I think the tribalism is mostly in jest. I've never actually seen two Linux users seriously fighting over their preferred distro or init system or whatever.

It's both.

Christoph Hellwig, a kernel contributor, and a bunch of anti-Rust fossils, were sabotaging Rust-for-Linux projects for using their C APIs for months until Torvalds intervened, and have been actively hostile and abusive against R4L contributors until they left the project. Summary by Aussie Linux Man.

XLibre, headed by a... shall we say, interesting figure, has attracted a rabid fanbase who are frothing at the mouth and calling Wayland woke DEI garbage that will destroy Linux. The first day of the git repo saw threats of gun violence, the antisemitic (((triple parenthesis))) dog whistle, openly transphobic statements by non-developers, and the owner's commitment to allow all of that under the banner of being "non-political". More context here, in the comments.