Today I learned complaining to Isabelle about a resident's clothes won't remove the outfit from their wardrobe. It will simply make them change into their default outfit for a bit until they decide to change to something else in their wardrobe again.
I complained about Julian's clothes, went to his house, saw he had gone back to his default shirt, checked his wardrobe and saw the shirt I gave him was still there. Within the next hour he was wearing said shirt again as if nothing happened.
Don't know if it's a glitch but it sure does seem like a pointless feature.