There are some who contend that the heroes of the Marvel Cinematic Universe are the modern equivalent of the Greek gods and other pantheons of the past. Like the Olympians, MCU superheroes use their fantastical abilities to lord over and protect humanity from all manner of supernatural threats. Also like the Olympians, MCU superheroes are occasionally prone to committing great acts of evil themselves.
Nothing an MCU hero has done can compare to the genocidal actions of Thanos or Hela - or the consistently worse actions of their comic book counterparts - but they’ve still done some pretty awful stuff by the standards of most people. And, sure, nobody’s perfect - but there’s a decent-sized gap between perfect and some of the heinous decisions made by these seemingly benevolent characters.