@studiofox That's the thing, it's not a "violation" in the same sense that an inappropriate image might be.
Copyright is a civil matter. You won't go to jail for copyright infringement unless it's value is over a certain amount usually. Even then, it's different in every country and since these companies are in no place to put a value on someone's work, and usually operate in many countries, they need to step aside and let the parties deal with it themselves.
When you're making a claim for something you own, you're not telling them "this is against the rules/they're breaking the law", you're telling them "this person is violating my rights, if you don't want to participate in violating my rights, you need to take this down".
I hope this makes sense and explains it. Though, I understand your frustration of seeing stuff that probably shouldn't be there because they're violating someone's rights.