What I'm trying to say is that the vast majority of mainstream philosophy is useless, but some of it is useful, and I gave examples.

I've also repeatedly agreed that most people should not be reading mainstream philosophy. Much better to learn statistics and AI and cognitive science. But for those already familiar with philosophy, for whom it's not that difficult to name 20 useful ideas from mainstream philosophy, then... why not make use of them? It makes no sense to draw an arbitrary boundary around mainstream philosophy and say "If it comes from here, I don't want it." That's silly.