I suspect because we've seen the shift from simply men who can't attract woman discussing it on the net to a movement that's obviously much more political. Again to me it feels the whole "pick up artist" culture that came to the fore a bit earlier, however questionable some of the "tips" that movement offered were the real attraction it has was IMHO selling a broader philosophy. That kind of idealised sociopathy has I think been on the rise in several different areas on the net appealing to disaffected men.
I think you see it somewhat as a reaction to the current political climate, the idea that paying lip service to PC politics is the be all and end all of society. A lot of men are likely finding out that this isn't improving their lot economically and I suspect that disingenuous nods to feminism isnt a stand in for actual empathy in terms of relationship success.