First, the bar for "guest speaker" is lower than for "tenured faculty." Yes, importance comes in degrees.
Second, I will admit to flippancy, though not on the order of suggesting an equivalence with Breivik. My comment was getting too long as it was, and I sacrificed seriousness for concision and out of impatience. Mea culpa.
Regardless of leftist or rightist motives, Rosenberg was a dangerous criminal and deserved to spend time in jail, though I think her sentence was too harsh. People who suggest that there are fewer mathematical geniuses amongst women than men don't go to prison, and in fact, I doubt that many would disagree with that statement. That was a specific example of gender differences in intelligence given in my high school psychology textbook. They're quite welcome, actually. More controversial is the proposition that this is a result of an essential gender difference, but people on both sides of that question are (typically) quite welcome. I know some exceptions here, but correct me if I'm mistaken in the typical case.
Let's return to what I've been saying all along: I have a problem with privileging bad ideas, but bad ideas are not to be automatically criminal. Yet there should be a cost associated with espousing those non-criminal bad ideas. Rosenberg's ideas were very seriously criminal: she faced a very serious cost. The cost of her past deeds in evaluating whether to invite her as a guest speaker has been reduced - though it still exists.
(Tangent: If holocaust denialism were to be banned here as it has been in France and Austria, I would be encouraging universities to fill Irving's schedule.)
Returning to the context, I took Paquette's list of "look who they'll invite!" as insinuating that there are no standards when it comes to the left, while implying that center-right ideas are verboten. That remains false.
First, the bar for "guest speaker" is lower than for "tenured faculty." Yes, importance comes in degrees.
Ok, what about Kathy Boudin or Bill Ayers?
I have a problem with privileging bad ideas
The question is who determine which ideas are bad.
Related: Heuristics for Evaluating the Soundness of the Academic Mainstream, Admitting to Bias, The Ideological Turing Test