This has come up in the Neo-pagans thread, but I do think there's a religion-shaped (or at least tribal) hole in the human psyche that has historically helped our species by promoting group cohesiveness, etc. It's still there, even as organized religions become less popular, and I don't think it's going away anytime soon.
Instead, I think what we're seeing is a buy-in identity and attempts to signal that identity to others as a substitute for being a member of a group bonded by a shared common interest.
I genuinely believe that on some level these people are signaling "I am the type of person who plays Nintendo games" and "I like cute things" because one of the most prominent modern virtues is self-expression (look at all the Disney movies, as an example, so so many of them are about "finding yourself" and "being true to your real self".)