Republican is the party of bullies. They pick on gays. They pick on the poor. They don't give women the right to choose. They are anti-science, denying global warming and evolution. I guess these were the people who picked on weaker/nerdy people or people who were different from them in school.
This is one person being violent to another. I don't think the republican party condones this behavior and is likely embarrassed by it. As far as I know they don't advocate literally stomping on the heads of their detractors as a party policy. Writing off an entire group of people because of the actions of one is probably unwise, I think, and certainly doesn't help in the battle against ignorance.
That said, we'll see how they respond to this and hope this guy gets isolated and ostracized in addition to being legally charged with assault.