You could get rid of both Biden and Trump, whoever replaced them would be beholden to the same imperial corporate interests and be just as vile with their policies.
You could do Putin or Zelenskyy in, and another capitalist oligarch would just take their places.
If Netanyahu disappeared tomorrow, Israel has plenty of genocidal politicians ready to fill his boots.
The real world isn't a Marvel movie, there is no single "ultimate bad guy" to rally against. The entire systems of these places need to be overcome.
Let's not forget, Avengers: Endgame ends with Iron Man committing magic genocide on all of Thanos' dudes
So it's not like they have an actual problem with it