>>286045661
>reasons
Well, other than degenerates being attracted to the game, one is that model makers just like making female characters more and there are less options for high quality male models. Another is that being an anime girl and being cute, without being the lewd kind or whatever, can also be a fun and different experience and people have found that it's not so bad. 
Also before the rise of VRChat and Booth, the primary source for any kind of anime model was MMD, and of course female models were the most popular there. That has carried over now and it has had profound impacts on the culture of VRChat that essentially perpetuates itself. The more anime girls there are the more people who want to be anime girls or degenerates come to the game. There is also a pressure on people to use anime girl avatars simply because most of everyone else is.