One of the "leaders" incites violence, one does not. There is no equivalence here at all between how Sanders talks about his opponents, and Trump does. Not close. There are certainly Dem leaders I don't like for groups/people they've supported, but NONE OF THEM are POTUS, or elected and cheered on by millions of people, publicly, for call outs of violence against his opponents. It isn't about extremism, it is about how one fights it, even on their own side. Or, in one case, encourages it.