I'm no fan of Milo Yiannopoulos. Regardless of his politics, I think he's a crude, insufferable, provocateur who's more interested in the shock value of his persona than his supposed conservative principles. All of that is fine. If he wants that to be his brand, and he's not getting violent, he's perfectly within his rights to be "that guy." I may not be into it but we have a little thing called the 1st Amendment, and it guarantees his right to say whatever he wants.
It also protects the rights of free assembly for those who wish to listen to him.