I'm not really sure you can argue birthdate is the thin edge of the spear when the standard Linux user database already had fields for location, email, phone number, and real name. None of which have been used for anything up to this point, and systemd-homed is not as widely used.
Yeah, Reagan functionally broke the system and every president and party since then has made tiny tweaks at best, this type of understaffing was common under Biden and Obama as well. Its just hit its breaking point.
Pretending this is a Trump only issue is covering for a whole lot of people who share the blame in addition to Trump.
People who can't operate a computer will somehow become gods at following instructions if someone calls "from Microsoft"
I agree with your second paragraph but I fail to see how the existing unused fields are somehow less dangerous or a "false equivalence" to a new unused DOB field which is significantly harder to use to deanonymize someone than their name, address, and phone number.