People who dislike fatties are not similar to supremacists. There is no real hatred of fatties and no desire to prevent them from attending the same schools, drinking from the same water fountains, and living in the same communities.
Not those exact ways, but yes there are ways people do not provide support to fat people. For instance, you can't find bigger clothes at any store, you have to go to a "Big'N'Tall" section, or a whole other store dedicated to "Big'N'Tall". Fat people are blamed for killing themselves on food when really it's an addiction just like a drug addict. Fat people are most often addicted to taste, and eat for the taste of food instead of for nothing other than hunger. Belts bigger than 40" are hard as hell to find, probably because belt makers think that when you're that fat, you don't need a belt! Or what about shoes? Wide shoes are hard as fuck to find, and I often dread shoe-shopping because I can't even pick ones that I think look nice. I'm damned to wear clothing I don't like because I wear them on the basis that they fit, not that they fit my style.
Not only that, but advertisement agencies, doctors, health instructors and everyday skinny people constantly guilt fat people into feeling bad about themselves, and they're just as emotionally sound as the next person, which isn't too sound. And don't, not for a SECOND, discredit the fact that fat people can't get nearly as much intimate relationships because of how society bashes fat people. How often do you see a skinny person with a fat person? Nobody sees beyond their weight and into the actual person, they're immediately prejudiced because they've been washed by society and everyday people that hating fat people and blaming them for their obesity is OK because being fat is wrong.
I bet people who were racist in times of slavery didn't think it was wrong because society and everyday people said it was OK because being black is just wrong! NOT comparing this kind of prejudice of fat people to the prejudice of black people is stupid, because all prejudice is the same. People are so quick to jump on the Black Slavery bandwagon when Americans were doing the same fucking shit to Irish immigrants during the same time period, some Irish getting even further abuse than black people would.
Just because America has become a professional at hiding how ridiculously prejudiced and judgemental we are doesn't mean it isn't there. And I'm not reaching for examples, or seeing prejudice that isn't there, because it so obviously is.