like some people act like cis and straight people are a dying breed and that they’re oppressed. they say that it’s definitely a thing and just as bad as queerphobia. however, while i do know that cishetphobia is bad, if that’s a word or term, IDK if it’s just as bad or if they’re oppressed or anything like that. i highly doubt the latter.
Usually the construction “X-phobia” is applied to someone who’s afraid of X, not to an X who’s afraid of something else.
But all phobias—including arachnophobia, claustrophobia, etc.—are harmful to the person experiencing them, before you even consider the harm it causes them to do to others.