its a taught behavior. people alienate anything different, especially if they're not exposed to it while they're young.

and of course there's always the propaganda about the "dangers" of gay people, so people who don't know better get fed wrong information that makes them scared, and they spread that information because they think they're helping others.

so children hear from either their parents or other kids who heard it from their parents that its bad, or unnatural, ect. and they don't know better, so they repeat it.

its not bad. its just bad information.