You're saying that if you go to them with a court order, they don't comply with it? So then have the court find them in contempt. This requires no involvement from Visa or Mastercard.
> And since videos could be downloaded and uploaded by anyone, removed videos quickly showed up on the website again and again.
How are they supposed to know it's the same video? Compare every video to every other one? The uploader would presumably just reencode the video or make whatever other changes to evade an automated system, and a manual system is infeasible. And no matter what Pornhub does, there are six quintillion porn hosting sites on the internet and it would just end up on a different one.
The correct answer is for the police to investigate who is continuing to upload them and impose penalties. Then no more uploads, no more video.