When people vote for someone with well-documented views then they are supporting those views, and supporting racist views is racism: there just is no way around that.
If you vote for a racist, you are a racist. You don't get to say 'oh, I voted for Trump but I'm not a racist', because you are. And you don't get to say 'all those people who voted for Trump are not racists': yes, yes, those people are racists. There are a very large number of racists, it turns out.