I don't understand about the hearing bosses for deaf people

I don't understand about the hearing bosses refused to accept deaf to take a job, because I heard some of my friends tried to take jobs but those bosses said no, because they're deaf, huh? They had no right to say no because of deaf reasons. Sometimes, I've felt that the hearing bosses are against deaf people, perhaps because deaf people are goofy, stupid, wild, and etc. But in fact: deaf aren't stupid. I love to being deaf. But actually, I'm hard of hearing. So anyway, gimme good reason why the bosses refused accept deaf people when they want to take jobs. I've noticed so many deaf people got cheap jobs, you know work in fast food resturant, publix, and etc. I've always wondering why don't they take a serious job and good money, but...I don't understand. I'm just confused. Will you example it to me very clearly?