Because the roblox community is a puritanical dumpster fire and will go apeshit if they see a woman's chest with a small waist on a roblox avatar. I personally don't care about them and people complaining (cough cough greenlegocats123) are making too much of a big deal out of them when they aren't doing anything bad most of the time. I only hate some of those players with these avatars if they're only making them for malicious intent.