Yeah, I don't see why NEGATIVES to your damage would be multiplied in that fashion. Critting would not make you do less damage. 1d2-4 and 2d2-8 could both only ever do 1 damage. I don't see how this is in the slightest bit relevant, though, the lowest any player character should ever be doing is 1d3, and that's only if you're small-sized with a dagger or medium and swinging unarmed (neither of these situations should have such god-awful strength)