To be honest, I'm still not 100% sure why everyone does it also. It is as easy as an attraction to larger women, for some people. Seeing as I am female, it's not that way for me. I am (as you might have noticed) a larger chick, so it actually made sense to me after a while, to show that big doesn't always mean hideously unnattractive as some people like to think and portray. Iit's a body size acceptance thing. All body sizes, really.
Also, I wouldn't make fun of Felicia, I used to have my room wallpapered with her sassy self.
Matter of fact, one of my first DA submissions was a picture I had done of a non-plump Felicia! She's in here somewhere. xD
ps. weight gain/expansion/bbw is not for everyone to like..or even understand. But acceptance is appreciated. My main problem with your "ew" was because people who like this type of art already feel ridiculed enough. They feel shame and the need to hide their interests from their peers, which also means that bigger women should feel like they have something to be ashamed of also.. see where I'm going with that?
Thanks for taking the time out to answer me. ^_^
Take care.