I agree with you about not wanting to share a government document with a shitty social media company. But companies that tie your account to your identity are going to insist on this moving forward. You have a right to complain, but don't be surprised if they insist. Their walled garden, their rules.

As a US Citizen, I have found that sending them an image of a US passport card is a decent compromise. The card itself is only useful for travel at land borders, but counts as Federally-issued ID. It has your name, nationality, passport card number, and date of birth, but not your address. The picture isn't really good for much. And, perhaps most importantly, all the ICAO stuff that is normally on your passport page is on the back of the passport card, meaning that a picture of just the front doesn't have all the info. Bonus points if you are old enough to have an expired one, then the card number will be useless.

There is very little damage a identity thief can do with just a passport card number. You are probably at more risk with your DOB being there. But, due to COPA, they probably have your DOB anyway. People can't even book flights with it, as passport cards are only for land crossings.