This abuse is against Grok's ToS, it was (!) possible because Grok doesn't want to be every user's overly prude nanny by banning nudity, they want to support artistic freedom. Unlike these dedicated websites, Grok's intent was good. Looking up "undress AI", there are a lot of results, and none of them are Grok. Yet Grok is being targeted, and exclusively so.
Think about this for a moment, and try to explain why.