Well, because they're 粉丝 girls, and 粉丝 girls are often a lot CRAZIER than 粉丝 boys. Also, I've seen some cases that some 粉丝 boys screamed like 粉丝 girls. Weird.
It's no threat to civilization if fangirls < fanboys.
Just stick with being good and you'll be fine. But if the threat of fangirls raiding any other site, beyond Fanpop, weeeeellll, my intervention will be required (at least one 日 of boy vs girl debates [stood for the outnumbered men, gave a one-liner, won] would be of use).
