If Himmler or (it is spelled) Goebbels were coming to speak, they would be 130-year old, undead, re-animated zombies and who would still be convicted war criminals. So your analogy is idiotic.
Last time I checked, Milo Yackoffinasock (or however you spell his last name) is not a convicted war criminal.
And yes. "Hate" speech is protected under the First Amendment. Particularly when the guy has not been charged, prosecuted and convicted for his "Hate" speech.
Instead you, since you brought up Nazis, are advocating for the exact same tactics used by SA Brownshirts who stood outside the doors of Jewish businesses and used physical violence and intimidation to prevent people from entering.
The behavior of the organized rioters at the UW who physically attacked members of the public who wished to legally attend an event is no different and mirrors those Brownshirt tactics.