It's a balance. Suppose you add this proof requirement. What happens then? It's not as simple as lots of legitimate amateur content producers facing additional friction. Most will make the explicit decision not to have their legal name and address associated with pornographic content. Others will upload their content anyway, without doing an audit of the different platforms' security postures or being aware of the likelihood of and outcomes from breaches.
What happens in a breach? Now, you're probably thinking, just require the platforms to be secure! But you can't simply will that into existence, and I guarantee you it's impossible. So ultimately you've made people vulnerable when they weren't before, and you're setting up a situation where it's pretty much inevitable that they'll be exposed and threatened by stalkers, deranged fans, and ideological zealots.
Let's suppose you bite the bullet, and say turning all the porn platforms into outlets for major porn production companies is the way to go. At least we've eliminated revenge porn, right? No. Large masses of people really hate that kind of mass produced porn, so they jump to foreign platforms that don't require complicated ID verification. These sites end up with the large majority of amateur porn content, along with the revenge porn. But they're now out of the reach of US law enforcement, so the victims of revenge porn would then be in a worse position than they are today.
Now we're getting to even more extreme measures. Maybe the US needs to build a national firewall to prevent the foreign criminals from penetrating our great nation and undermining our morals with porn that's unapproved by the Feds? China is way ahead of the game on this, in that pornography is outright illegal, and it has sophisticated internet security measures that are exceptional in breadth and depth by Western standards. How's its war on porn going? Spoiler alert: it's lost it. Perhaps it could be a moment to build cross-cultural empathy, as Chinese netizens exchange tips with Americans on how to use Shadowsocks to avoid the censors and access amateur porn.
Requiring ID verification is one of those things that sounds good and moral on its face, but has so many unintended downstream consequences that exacerbate the original problem while making things generally worse.