I dunno why you're wasting your time on him. I mean, he thinks that HC/M raiding started declining when TF was added to LFR
That's quite a delusion, if you ask me.
HC raiding scene started declining
faster when EQ-style raiding schedule and etiquette became things of the past, and splits and 8+/7 raiding during progression became the new norm.
And ofc, raiding in general always was and always will be a niche activity,
it's prob the most popular one among all activities WoW has to offer, but it's still a thing that interests only a certain group of people.