That's not super relevant to this case, because TikTok itself is banned in China; Chinese users have to use Douyin, which runs the same platform but doesn't share content with TikTok.
Seems to me that it's not banned at all, they just release a region-specific version for a specific market.
Heck, region-encoded DVDs weren't a form of ban, don't you agree?
Tiktok is the same exact service with region-specific restrictions, primarily motivated to comply with local jurisdictions. That's it.
I’m guessing that the international tiktok hosts content that wouldn’t be allowed on China, and the CCP isn’t interested in having the workload of censoring the rest of the world’s content.