Visiting the Heineken website in the U.S. requires that you assert you are over the age of 21. Texas has instituted I.D. verification for pornography.
Regardless of how you feel about this law, it is not accurate to say the U.K. is unique in implementing it.
It’s not uniquely U.S. at all
What other countries require ID checks for services like Discord?
The U.K.’s implementation of this law is much more unique than you’re claiming.