Anthropic does their best with banning accounts. As the result, shady API reselling market emerges. OpenAI on the other hand doesn't really discriminate based on a country like that (but a VPN is required nevertheless).
GGP said "legally prohibited" not "against terms of service"
Keep in mind the only law that applies to them is Chinese law, so even if violating a term of service was illegal in America (it isn't) it would also have to be illegal in China to justify the statement.
