My thoughts as well, even more so after seeing the only GitHub Workflow they have is actually for closing Pull Requests with a default response:

https://github.com/mozilla-firefox/firefox/blob/main/.github...

It’s interesting how pull requests remain the only tab (apart from code) that cannot be disabled by the repo owners.

I get it from GitHub’s perspective, it’s a nudge to get people to accept the core premise of ”social coding” and encouraging user pressure for mirrored projects to accept GitHub as a contribution entrypoint. I’m impressed by their successes and would attribute some of that to forced socialization practices such as not allowing PRs to be disabled. I’ve grown to dislike it and become disillusioned by GitHub over the course of a long time, but I’m in awe of how well it has worked for them.