Bullies dont need a reason, they bully for the sake of bullying. They choose to behave the way they do. Its unfair to blame their parents for their behaviour. And in that regard, it would be of little help to "educate" their parents.
Also this "line of thinking" about educating people that gays are normal, not different, etc etc etc seems out of context. I mean are all cases of bullying-affected suicides related to gay teens? There are bullies who harass people to the point where they commit suicide. And not necessarily gay people.