The government really shouldn't be telling us how/what we can compute at all.
But on this specific point - It's a bellwether. They're doing this to lay the groundwork and test the waters for compulsory identification and/or age verification. Getting MacOS and Windows and Linux and etc to implement this WILL be used as evidence that compulsory identity verification for computer use is legally workable.
>The government really shouldn't be telling us how/what we can compute at all.
You could say the same thing about restaurants. "The government really shouldn't be telling us how/what we can cook at all."
When you are selling a product to the public, that is something that people have decided the government can regulate to reduce the harms of such products.
And if the implications of that aren't clear - that would either be unenforceable or be in effect a government rootkit+DRM on every device.