Well, they didn't charge for it, right? They're retroactively asking for money, but they could have just locked their content behind a strict paywall or had a specific licensing agreement enforceable ahead of time. They could do that going forward, but how is it fair for them to go back and say that?
And the issue isn't "You didn't pay us" it's "This infringes our copyright", which historically the answer has been "no it doesn't".