Meta/Facebook and Google/Alphabet are very different from Twitter/X. The first two created parent companies under which their large brand names still exist, but are now managed along with their other properties (Instagram, Snapchat, Waymo, Deepmind, etc.) Musk, meanwhile, is trying to completely burn down the Twitter brand for some incomprehensible reason.

Actually it’s worse than nothing. Youtube promotes comments based on engagement, so while only an upvote increases the tally, voting at all still makes it more visible.

It’s a bug. I’ve been getting it too, pretty sure it’s related to how much stress the server is under. Give it a few minutes and refresh the page.