It is not fair to tar someone based on who supports such person. As Reagan said, about kooks supporting him, is that they are supporting me, I am not supporting them. I think this ad is a waste of money. I don't think most folks think Trump is a racist. He's a nationalist, and a xenophobe, but not a racist. Bashing Trump for his fondness for Putin is fair game.
In not so enigmatic ways he has drawn this support intentionally. No other major presidential candidate in the past few cycles has drawn this sort of support. If you want to vote for the guy, go right ahead, but don't make him out as not being a racist, because he is and it's fair game. He was racist long before he ran for President.