After all, they have no way of knowing any of us aren't 12 without that information.And equally important, they have no way to really know we aren't 12 even *with* that information.
For example, a 12 year old could easily provide a photo of mommy or daddy's ID. Or a photoshopped copy of an older friend's ID?
Basically, any reasonably secure verification method will need to be equivalent to the KYM (know your customer) process used by banks --- and a lot of *legal* users will be excluded because they can't pass the test. Many teenager's lack a reasonably secure identity document.
The USA suffers from an over abundance of ignorance and stupidity --- and this extends all the way to the government level.