Left-Wing YouTuber ThoughtSlime has a good video on this topic. The video is called Is Batman a Fascist? , but he talks about the idea of superheroes being fascists in general and why that is wrong.
Superheroes can be played up as fascist, but they are not inherently fascist by any means. If anything they're the opposite. Superheroes fit the socialist principle of "From each according to their ability, to each according to his need."
It is disheartening that some people are quick to label something as problematic just because a few problematic people like it. Not only is that tribalistic, it also comes off as gatekeeping. And gatekeeping can be dangerous. I mean, do we really want to send people the message that Fascists are like their favorite superheroes? Think about the consequences of saying something like that. Going around calling superheroes fascists is a gift to actual fascists.