Gadol hadorah, what source do you have that interprets that stained clothing on a talmid chacham is a matter of tznius? All classical meforshim understand this to be an issue of kavod hatorah.
It’s ironic that some frum girls complain tsniyus is stressed for women more than men, and yet many a frum girl wears tops that show collarbone & forearms and skirts that reveal calves, while frum men typically don’t wear shorts, and rarely wear short sleeves or forego wearing a collared shirt in public.