The right response if you don't like the guy is to stay home and ignore him. Treat him like a nobody. That is what would happen if I came to speak (and I am a pretty good speaker). The speakers series organizers would say, "Thanks Mr. Blinkermann for you offer to speak. We will see if we can fit it in the schedule, Don't call us, we'll call you." And that would be it.

Mr. H will be just as happy seeing the backsides of college students in the auditorium as he will be seeing their smiling faces-- as long as people are there.

So do the right thing, When it is time for Mr. Horwitz to speak, go have a latte (and make sure to sprinkle a little cinnamon on top)!