Perhaps because it asked for your social security number.
/from someone who never lived in the US
handing out your SSN makes it easy for someone to try to open lines of credit, credit cards, loans, etc. in your name. You'd need other data, but that's often trivial.
SSN also wasn't designed as a universal ID and has a few weaknesses, on top of being shoehorned into a role it wasn't meant to fill.
For example: in the US, drivers licenses are issued by state (what would be called a province anywhere else) governments, not the federal (i.e. national) government. My first drivers license used my SSN as my license number, but if I had asked, the state government would have been required to issue me a license with a different number.
These laws were passed because it got to the point where just getting someones name and SSN were nearly sufficient to completely steal their identity.
It's also why the US Senate designed to represent states like the EU council, was never intended to be proportional.