This is the wrong battle to fight
There is no way to remove all of the bad content they will just upload more on different sites and send out the new URLs.
So what do we do?
The way to win this battle is to upload so much $hit content using the search terms that would find this horrific content that it becomes completely invisible on the internet. Then every time someone searches for ISIS or hate filled content or similar they will end up with an episode of peppa pig or teletubbies. That is how you fight a war of information