Why is it that whenever I queue into alliance raids and I get a tank that says they're bad at tanking or they don't know the raid, it's always the same exact tank that sits there provoking each main boss.

Just let the one of the two other tanks deal with it. It's not like neither of them are willing to MT considering you're trying to provoke the bosses off them.

I've seen this happen literally every alliance raid I've done this week too, from CT to Aglaia and Euphrosyne, and it's actually starting to annoy me a little bit.