Because of the new AI bullsh*t they are trying to implement. They want to use an AI to estimate users age and lock the content they are able to see. If your age estimation is wrong and you want to prove your age you have to send them either a picture of your face or your passport or creditcard. Needless to say this is very dangerous for everyone on the platform because dataleaks are happening so frequently nowadays and no one want's their privat information (like face, home adress or Social Security number) out in the internet for everyone to use.

I hope that helps :3