

This is a law that companies are required to implement or stop making business in the states enforcing that law.
You probably feel that companies should just stop doing business in those states “to show them”. Sadly a lot of profitable Linux companies that fund Linux development disagree with your high morals. They want to continue doing business there.
Adding that field help those company comply with the law and doesn’t hurt you in anyway except maybe taking few bytes in your disk drive.
Even if the field is not added, those companies would come up with another place to store date of birth or even use systemd fork.
Its not like they will say since we can’t store date of birth in systemd’s user model then we’ll have to abandon this project and close our branches in those states instead.

I have started with Mandrake (later renamed to Mandriva) then went through few other distros before settling on Gentoo.
Gentoo installation is one of the most complicated because there is no installer, you do everything yourself.
This is like buying car parts and assembling them together into a car using a manufacturer’s manual. its painful but once the car is assembled you almost never have to take it to a repair shop. Not because it doesn’t breakdown but because you know well how it function and thus how to fix it yourself.