Do I think that Trump wants to kill millions of people or anything like that? No. I'm pretty sure he doesn't.
At the same time though, his rhetoric is dangerous. When a candidate wants to claim that a whole group of people is composed of rapists and drug dealers (and a few good people I assume), or that we should only be letting certain religious groups into the country, or that maybe we should register a group of people... Well, that's just stuff that we should be VERY cautious about.