> Verrucas, athlete's foot, 'fungus', general foot sweat.
Problem here is that this is a self fulfilling argument - most of these conditions exist because of people keeping their feet cooped up in tight sweaty footwear. Go barefoot and these problems disappear.
> you can quite easily hurt your feet climbing barefoot - if you need any proof give it a go
I've climbed several VDiffs barefoot, along with 2x 3000ft peaks. Its refreshing. Don't knock it till you've tried it!
I'm not suggesting that barefoot is the way to push grades, or even a sensible way of regular training, just that automatically banning barefoot climbing while allowing climbing with sweaty, greasy hands with flappers and grazed knuckles is illogical.