YouTube does depending on the content you upload
I had to validate my own documents with Google because a small animation I had posted had made use of copyrighted stuff, and when I went to edit it to remove the copyrighted music, it kept nagging to “validate who I am”
You’re not forced to link your account with your real identity in fedi.
AFAIK neither are you on reddit or other platforms
YouTube does depending on the content you upload I had to validate my own documents with Google because a small animation I had posted had made use of copyrighted stuff, and when I went to edit it to remove the copyrighted music, it kept nagging to “validate who I am”