See, when we talk about genres, there are really two sorts of genres.
First, there's Drama, Comedy, Horror, and Suspense (and possibly Romance, depending on how you look at). There's no required content for any of these genres, merely that they try to evoke a certain emotion. Comedies make you feel amused, Dramas make you feel empathetic with the characters, Horrors make you feel scared, etc.
Then there are more concept driven genres, like Western, Science Fiction, Fantasy, Historical Fiction, and (again) possibly Romance. These genres are defined by the setting and/or basic tropes they use to tell a story, not by the emotion they invoke, so most stories in these genres also fit into the first kind of genre (Dramatic Westerns, Comedic Fantasy, Horrorific Historical Fiction).
Superheroes is one of the second kinds of genre; people with superpowers and usually costumes or unusual appearances fighting evil people is only a little less broad than the Western genre, and nowhere near as broad as Science Fiction or Fantasy. However, just because Superheroism is a genre doesn't mean superhero stories can't fall under lots of other genres; most are either Science Fiction or Fantasy (often both), plenty have large amounts of Drama involved, many have Comedy, and I'm sure I could track down quite a few Horror or Suspense themed superheroes if I tried.
First, there's Drama, Comedy, Horror, and Suspense (and possibly Romance, depending on how you look at). There's no required content for any of these genres, merely that they try to evoke a certain emotion. Comedies make you feel amused, Dramas make you feel empathetic with the characters, Horrors make you feel scared, etc.
Then there are more concept driven genres, like Western, Science Fiction, Fantasy, Historical Fiction, and (again) possibly Romance. These genres are defined by the setting and/or basic tropes they use to tell a story, not by the emotion they invoke, so most stories in these genres also fit into the first kind of genre (Dramatic Westerns, Comedic Fantasy, Horrorific Historical Fiction).
Superheroes is one of the second kinds of genre; people with superpowers and usually costumes or unusual appearances fighting evil people is only a little less broad than the Western genre, and nowhere near as broad as Science Fiction or Fantasy. However, just because Superheroism is a genre doesn't mean superhero stories can't fall under lots of other genres; most are either Science Fiction or Fantasy (often both), plenty have large amounts of Drama involved, many have Comedy, and I'm sure I could track down quite a few Horror or Suspense themed superheroes if I tried.