Q: Is it possible to hack a large number of adult sites hosted all over the world and take them down?

A: In order for this to be possible, all of the sites would need to be running on the same operating system, using the same web server software, so that they would all be subject to the same vulnerability. In addition, the vulnerability would need to be a zero-day attack – a vulnerability that the software developer did not know existed. And even if all the stars lined up to allow this to happen, a patch for the vulnerability would be crafted in hours, if not minutes, and the sites would be back up and running within hours using backups.

All that being said, not only is this cybercrime, but for most of the developed countries, and most certainly in the USA, it is cyberterrorism. The criminal hacker would most certainly be put away in a very unpleasant place for a non-trivial amount of time, their life savings vaporized in a failed attempt to defend against the legitimate charges, and should they ever be released from that dark place, would likely never be allowed to use a computer again.

All because of their questionalble moral high ground.