Yes, Japan has numerous sub cultures. Weeboos are westerners who attempt to become a part of that sub culture.

For example, the cat girl uwu, whatever, yeah, that's a sub culture in Japan.

Loli and shotcon, yes, that's a sub culture in Japan.

Futanari, chicks with dicks, that's a sub culture in Japan.

Traps, that's a sub culture in Japan...

If you can think it, there's more than likely a sub culture surrounding it; hence the Rule34 rule.