I'm not attracted to men who weigh 400 pounds. I was not attracted to them when I weighed 300 and I'm not attracted to them at my current 145. That does not mean that an attraction couldn't grow based on familiarity, but they're not catching my eye in the grocery store.
It's pretty much just biology; it's not a moral weakness, it doesn't make anybody a bad person. You either get a pit of the stomach feeling about somebody or you do not. Evolution has programmed people to look for signs of health and fertility and the obese don't exactly radiate either one.
A lack of physical attraction is not, however, an excuse for being rude or dismissive. You don't have to want to date somebody to be polite.
Current Weight: 144 lbs.