Considering the industry PornHub is a part of, they should be well aware that there is a lot of potential for abuse in multiple ways. Considering that the topic of consent has become important the past years, I would say it's in Pornhub's best interest to be very strict about the content on their site, and to be very open about the way they're handling all this. Trying to shrug off any responsibility is honestly not a good look when it comes to stuff like this.

And of course stuff "inevitably" slips through when you don't even have a proper verification system in place. If anyone can just upload revenge porn on your site, I think it's safe to say your system has failed.