I think the statement that most American find fat people not unattractive or how ever it was worded is flawed and more of the PC Bull Shit that is harming this country.
First in my opinion the term over weight is different than being obese I mean technically aren't most weight trained people over weight I mean surely most Olympia contenders stepping on stage at 5'8" or so and weighing in at close to or above are certainly over weight by normal physiological standards IE a average size healthy person unless they are 7ft or more would not be carrying 300lbs.
Obese people however are carrying extreme adipose tissue stand a 230lb weight lifter next to the 230lb ass crack showing plumper stuffed under your sink and while they may both be technicaly overweight the differance in body composition is where the term overweight becomes a misnomer.
(No offense to plumbers as a whole)
I think people have been forced to conform there true opinions by a society which warns us not to offend people.
If you asked the average woman or man privately if they would like a hot sweaty passionate encounter with someone 100lbs obese. vs. their idea of lets say Brad or Angelina. of course they would say no.
Chubby chasers and other such fetishes aside.
I truly beleive most people have no ill will against the obese but I also believe that most people do not want to be obese or want there partners to be.
This has nothing to do with love or people who like a little extra cushion love is subjective as is attraction.
Obeseity connotates unhealthyness and fitness exudes health.
While most people may ignore weight gain in a spouse or not mention weight gain in a relative. That does not mean they don't mind or if they had a choice would not like to get their arms completely around their lover like they did in the past.
I have never seen anyone who sees someone they know who has shaped up who has not said how wonderful they look or hasn't said to them afterwords I was always so worried about you.
Not finding obesity attractive does not make you a bad person. any more than obesity makes a person undeserving of respect and kindness.
But I do beleive Political Correctness and perhaps kindess guide the answer to whether or not Most Americans find fatness unattractive.
Just a thought.