America is an ally, if not formally then the shared westernism. China is most definitely not.

Well, you could certainly see why the situation changes when the service is controlled by an adversarial government. At least the US services are only clandestinely influenced by the US government. TikTok is practically a Trojan horse

Kinda. Many Americans run around with a notion of some kind of noble entrepreneur who provides the bounty of endless choice in consumer goods, even if it's a corporation. The fact that many different brands come from the same factory tends to be overlooked. Americans are also unique in their tolerance for constant advertising where other cultures would consider it gauche and intrusive.

TikTok is imo goddamn scary. It is explicitly set up to hook people with gamification techniques, showering likes on new users so they come back for more. Only the subject matter is often politics, activism and intertribal warfare.