TikTok says it’s not the algorithm, teens are just pro-Palestine — The company denied allegations that it has been promoting pro-Palestine content in an effort to sway American opinion

Well we know for a fact that China has it's own Douyin (Tiktok) app and that it prioritises stopping any inkling of random social movements/organisation through social media.

So this isn't really a mystery at all. Within China they are subject to their laws. Elsewhere they follow global norms.

I actually think all the furore about China and Tiktok was really not about Chinese control over Tiktok in the West, but about the West's own control over Tiktok. Much like how Huawei was booted for not allowing US intelligence agencies to put in backdoors, rather than actually enabling spying itself (this came out last year iirc).