I mostly just find the whole thing rather sad, especially since it comes from a creator whose work I used to enjoy a great deal. (My change of opinion is more due to my dissatisfaction with more recent output than "the late unpleasantness.")
I also think that trying to control discussion and spoilers, or relying on "surprise" twists as a storytelling device, is a fool's errand in this day and age. And finally, I can't help but wonder if Mr. David allows his opinion of other venues, such as conventions, to be wholly defined or unreasonably influenced by his encounters with the inevitable disagreeable few rather than the vast greater number of temperate, appreciative fans.