I've seen many people get teased about being skinny. It's like being tall. People that aren't tall think that it would be great to be tall, so they think it's just fine to call a tall person a giant. Many people think that it would be great to be skinny, so they think it's just fine to tell a skinny person that they're skinny. People are significantly more sensative to fat people, posibly because there's more of them in our country.
I'm rather overweight, but I've been losing quite a bit lately. Personally, I think dating a fat person is like dating a person with lung cancer. You aren't judging them based on appearance per se, but based on mortality. I personally wouldn't want to date a 500 lb woman, simply because I would know that she wouldn't be around for very long. Also, before I started to lose weight, I had no self controll with food. Food was an idol to me. Many times, I placed it before God. Now, food addiction isn't the only way that people get fat. People can be so by not having enough sleep, and other reasons. But typically, in a society such as ours, people get fat the same way I did. Thus, even though it's unfair, when I see a fat person (and this really is the pot calling the kettle black) I think that person might have an issue with self controll.
But on the other hand, who doesn't?