It's not the job of the operating system to protect children. Social media is bad even for adults, to my point of view why they don't address the source of the problem, banning what Instagram, TikTok, etc. is doing that is bad even for adults, and don't make laws that restricts even more what a person can do with their personal computer (if this law comes into effect it's like saying it would be illegal to run Linux or whatever OS that doesn't implement this bullshit)?

Well, surely because the government is full of investors in Meta and uses Meta for their propaganda, and possibly because the government wants more data to put on their databases that is used by ICE and other agencies.