If you are giving them your PII to verify your identity, doesn't that means they already have a PII database to compare you against?

Id be pretty shocked if anybody here had a FB account, under a pseudonym, and they actually believed they were keeping their true identity hidden from FB. If you have an account, they know who you are. Verifying your ID is a due diligence on their part to CYA.

How many people, saying they would never give info over to FB, willingly hand it over to the fintechs like Robinhood?