I think his point is that being quick to throw out exaggerated extremist views when describing a group can be tedious (if not offensive) to other members of the group.

Honestly, how many mentally-ill extremists who happen to be vegetarian do you think are going to risk jail time and notoriety just to breed ticks (!) and distribute them hoping to trigger this unusual side effect while knowing that they could just as easily spread other diseases?

What other diseases would prevent people from eating meat?

Phenylketonuria, for one, though that's not contagious, and prevents one from eating all protein.

Wait what, how did "mentally ill" suddenly drop in there?

Where would you place the likelihood that somebody who intentionally makes ticks bite people is well-balanced and without mental issues?

Their ethics put harm to animals on the same scale as harm to people, and so they regard the rest of us as complacently witnessing something like mass murder. Just because we entirely disagree doesn't make them crazy, though their ideas make it hard to coëxist with us.

I'd place them somewhere towards the "dick" end of the scale of "dick or not dick".