Why do guys make fun of chubby girls and won't even consider dating. But then the ok with the girls becoming a chubby guy :/

My girlfriend can be pretty chubby <br><br>Pretty fucking chubby. But I'm really ok with it and I love her a lot<br><br>A lot of guys won't consider dating a chubby girl because they think they are disgusting and ugly. <br><br>But then they will be ok with the girls becoming a chubby guy and ok with then dating a chubby guy <br><br>Like wtf? <br><br>Isn't that double standards?