Douyin follows Chinese law which is why it has these restrictions. TikTok does not so it isn't allowed. Kind of weird what happens when countries pass legislation around activities they don't want instead of just trying to ban a foreign app while allowing all of the same dark patterns in the domestic competition. China just does a better job of protecting its citizens from this sort of thing. The US could have laws around social media for children like China, but they are more interested in perpetuating the yellow scare and maximizing profit.