Blanchflower is apparently some noted economist, with over 60,000 followers on Twitter and a blue checkmark next to his name so must be a fairly prominent figure, so it is hard to understand why someone of that stature would suddenly decide to make a jackass of himself both in front of all his followers and everyone else in the world on a very popular public forum, by ongoing vitriolic trolling of sufferers of a serious disease.
He is apparently friends with PDW. The common denominator with any supporters of PACE seems to be that they are in some way affiliated with the authors. I have yet to come across any independent researcher that would be willing to stand in defense of it.