Why is that? Or am I doing something wrong?
Most Helpful Girl
It's probably just because of stereotypes. Just be yourself and you'll find someone who appreciates your interests.1
Most Helpful Guy
I am a bit in the same boat as you.
What I would suggest to you is first, online dating probably not the best way to go. But if you do go that route, vaguely put anime and don't go listing all of it. Same with games, say you play games, but don't go listing it.
Second I suggest trying to meet them in real life. It's hard because most anime fans and gamers sit at home all day. But nevertheless, you should give it a try.
Some places where you might find the rare gem we all know as a gamer girl is:
Bookstore (manga section)
Comic Book store
Movie theater (special screening of an anime movie)
Arts and crafts store (this one is stretching it, but some girls like to draw and create cosplays)
Also, I highly advise against conversations. If you want to know why just ask.1