You might ask, "Why is he naked?" You might seemingly reasonably demand to know whether he is doing anything untoward to his poor kitty. Perhaps he's disgusting. Perhaps he's a nudist. Perhaps he has simply failed in his quest for a super-suit tailored to his power of super strength. Perhaps he's just Greek.
But... having had to do the same myself, I can attest to the reason.
Skin heals. Clothes do not.
And those claws are going straight through the clothes anyway.
