Reject a PR?
I provide feedback on PRs. Then the owner of the PR adjusts it to accommodate my feedback and once I'm happy with it I approve it and we merge. If you're working in a place so cancerous that you can't just leave a comment on a PR reminding someone to update the comment they forgot to update I don't know why you're still there. This is called code review and it's common practice. If all you ever do is approve PRs then you're not doing code review and you might as well skip the whole PR step and let people merge into main as they please.
In any case your argument still just boils down to "I work with a bunch of stupid lazy dipshits" so why bother doing anything at all then? Write comments, don't write comments, write tests, don't write tests, do whatever the fuck you want because you're surrounded by useless dipshits and nothing you do matters anyway. Might as well write some comments for your own sake, everything's a ball of mud anyway it doesn't matter.
I'm gonna keep doing what I think is right in my sane corner of the world. And honestly I don't believe you. I think these excuses are just that. Excuses. I've been around quite a bit and haven't seen anything like you describe. Sure there's plenty of lazy dipshits but you don't have to sink to their level.