China is, when it serves their primary interest of deflecting criticism from the operation of their very extensive totalitarian/authoritarian system. IIRC, they put out "human rights" reports all the time to that end that do stuff like criticize American prison conditions.
> or was it Americans who got upset about Israeli treatment of civilians?
It's worth noting that TikTok could (and probably would) be used by the PRC in very subtle ways, that would be missed in a distinction of "is it Chinese people speaking or is it Americans." I think the influence mechanism would almost certainly consist of giving artificial boosts to American voices that unwittingly serve PRC goals, e.g. anti-war activists if China invades Taiwan. They could even strongly condemn China as a warmonger, but their elevation would still serve Chinese goals if they spread the message that the US should stay out.
And given that the PRC has access to all the TikTok data (I believe no claims the could not access it), they can probably very effectively figure out exactly the voices to elevate that would do their job effectively.