For one, they're not weebs they're just anime otaku, but also that is only a subset of anime and it's mostly just a judgemental stereotype. They have ads on the subway for birthday events for popular anime characters ffs. Many pachinko machines are anime themed, including after late night anime which are the negatively stereotyped ones. You know who doesn't have enough money to be a profitable target for gambling establishments? People with no job living in a basement.

And that's all while ignoring that pretty much no one chooses that life style voluntarily and I see no reason to make fun of these people.