I wonder how often it is unintentional or somewhat polite. As a kid I got into this habit of not really looking at obese or disabled people because I didn’t want to seem like I was staring at them like some of my slackjawed peers might. I think to an extent this bleeds over into adult life. Obese or disabled people might think it is malicious but the behavior might really come from good intentions at least to some degree. A boring dystopia sort of situation IMO.