Exactly this! There is a dad at my DC's school who does pick up. He's the boyfriend of a woman I vaguely know and he repulses me. Never spoken to him.
I'm fat myself, so this isn't a body shaming thing, honestly. But I've never seen him in anything other than shorts. Rain, snow, shine, wind, frost.
They're always too tight and do that shuffle up the inside of his thighs so they look like his bum is trying to eat them. In addition to the shorts horror, nothing else he wears matches and he just looks so... icky.
There is just something about him that I find grotesque and the shorts I think are what set me off.