>>723840084 (OP)
Because they're gross. People are fat because they choose to be, which often dictates a lack of mental resolve and laziness.
A couple of extra pounds isn't a problem, when you're such a lardass that you've lost the ability to run, you should start to hate yourself.
>>723840084 (OP)
See your photo is chubby, not fat. It can be hot in fanart, even IRL if she has a big ass and tits.
But this thread will devolve into lard monsters
>>723840084 (OP)
Being fat usually serves no purpose narratively, so there's no point in designing someone that way. It would also be weird in settings where the characters are meant to pretty active, which is most games.