When the villain of the story is 100% in the right, so the writers make them do something extremely evil so we can't root for them.
Examples are mostly from Marvel shows but they're the best examples I can think of off the top of my head:
Falcon and Winter Soldier. The villains are refugees who were forced out of their homes once the second snap happend and all the people who were dusted come back. They think it's unfair that they should be forcefully evicted from their home and be left homeless. And then they blow up a hospital to "send a message" or whatever the fuck so we know not to take their side.
Secret Invasion: The villains are shapeshifting aliens who did work for Nick Fury under the condition he find them a new home, and he didn't for decades so they're understandably pissed off. And then they blow up civilains to "send a message". Again.
Inhumans. Honestly this one is the worst of it. The heroes are the aristocracy of a group of moon people where when people come of age they undergo a procedure that will unlock their superpower. If you get a useful or sexy power you get to life in luxury with the royals. And if you have no power or an ugly power your'e sent to mine in the slums. The villain is the brother of the king who has no powers but gets to stay because he's the king's brother and he's like "Hey, this is kind of fucked up." and he's right. And worse of all he doesn't even do that much evil, all they do is make him perv a bit on Meduca out of nowhere so now you know not to side with him.
Feel free to leave your examples below, or let me know if this trope has a name. Please, i'd love to know.