The less anonymous the poster is, the easier it gets for law enforcement to find them and enforce the laws against posting revenge porn or unconsented videos. Once a video is marked that way, it's relatively trivial to remove other instances of it.
IDs don't prove your real identity, especially online.
I can’t think of anything else than phone numbers and IDs which they could require for uploaders. Do you have any other ideas?
But this would have a horrifying, chilling effect on marginalized communities. Anonymity allows for one to publish marginalized interest works and trans-oriented contents.
This is especially important for less-than-safe jurisdictions, for which even bog-standard sex workers may well find themselves in the crosshairs of a fascist government, or even grass-roots persecution from far-right sources using hacked data! It is, after all, only a matter of time for most any web site in this day and age for a user-data compromise.
These kinds of policies lead to harassment, violence, and imprisonment for many.
Unfortunately, it's not as easy. The tube sites have understaffed support and, as the credit card processing ban on Pornhub has shown, consistently made life hell for affected people. These sites are blatantly ignoring even the most basic requirements of being good citizens of the Internet.
So what? Even if I'd require e.g. a phone number of every uploader it wouldn't change a thing. XVideos would still only be able to react, not preact. Content would still remain online, until someone reports it. If someone uploads your porn tape and you're the original author, just send a DMCA and it gets taken down. No problemo.