Unimpressive; the worst he has is that someone made a groundless complaint that was handled perfectly well in 2009, and he worries that someone will make another one one day (though it seems kind of telling that they haven't..?) and it will go differently. Why not get someone who's actually been harmed by this change in culture to write about that?
The important point here is that he's changing his curriculum to avoid provocative works, so he doesn't get in trouble. If that becomes a widespread practice, we'll have a serious problem in higher education.
I think that the rather spurious grounds that he identifies for the fear motivating those changes is also important, particularly, it is important in identifying the source of the problem -- which is not, contrary to the headline, his liberal students, or even his students more generally.