I get it. It’s one of the most innocuous “attacks” you could make against someone, but it also seems like stuff that other people would find harmless is what really gets under his skin. Like, call him a fascist, a criminal, manipulated by the Russians (all of which are true) and he just makes that stupid, constipated grin and his base eats it up.
Talk about how weirdly tiny his hands are, though, and he’ll make sure to run into you personally on the street, once a week, for the rest of his sad life, to show you that, actually, his hands are perfectly normal. Larger than average, even. His ego can’t handle being considered strange or abnormal in any way.
So the idea is the “does she look tired to you” (credit to Doctor Who) attack. Something quiet, innocuous, maybe even whispered to someone else, that is almost guaranteed to make him rip out his hair plugs. Can’t effectively parrot Russian propaganda if you’re having a meltdown about people calling you weird. Maybe it’ll be the thing that finally short-circuits his hateful black heart.