I have not been to a TARGET STORE since they refused to sell me a DVD of old Randolph Scott westerns from the 1950s. They wanted proof I was over 18 years of age as those movies were considered UNRATED, same as hardcore porn.
I was 64 years old at the time and looked every bit of it.
When a store asks me for proof of age I just point to my bald head.
It gets everybody around (including the cashier) cracking up....
Blame the Government. At least in NY State anyway, anyone selling restricted items (in particular alcohol) must verify to the State that they are asking for proof of age and have a system and employee training in place to do so.
So big retail outlets simply scan your ID for their database in case they are audited by the State