It sounds to me like the fat haters have a problem with gluttony. Sounds like some kind of moralistic holdover from their Puritan past. I often feel that taco guy who pops in to rant now and then also has a huge Puritan streak with his irrational hatred of dietary fat. I have learned over the decades that it is not wise to look down on others because whatever it is that you feel superior for not having you will one day wake up having exactly that.
Female, 5'3", 50, Starting weight: 163lbs. Current weight: 135 (more or less).
I can squat 192.5lbs, press 75lbs and deadlift 210lbs