Tencent is doing this to comply to Chinese laws. They won't do this if there is no such law. And the law says: "internet gaming companies have responsibility to not provide internet gaming service to minors between 10pm and 8am". I am sure tencent won't want to do this if they had the chance. 1) it limits their ability to get play time and sell to kids. 2) its more work on their end.
So the main problem here is the law. Not Tencent. But many Chinese people support and even called for this law. The supports for this law is cultural, circumstantial and societal.
In the US, Tencent should adhere to US laws and cultural customs. First, for this specific case, Tencent won't implement it outside of China because 1) why would they limit their own ability to make money 2)why would they not align with US culture? Second, If US has a law that bans using facial recognition, all companies will comply and these issues will not exists. You can enforce practices and values through laws.
Also this is Tencent specific system. They are using facial recognition to verify the current user is who they say they are. Just like IPhone has face ID. Because for other verification methods, kids just bypasses them. And I believe they only do verification ones during the banned hours. It doesn't consistently monitor you. The law targets online gaming providers, and fines them if they provide service outside the allowed hours. It doesn't incarcerate kids. Law enforcement doesn't track kids playing games and when they play. And Tencent doesn't share kids data with law enforcement.