Anyways, the article simply says that they found teeths with Neanderthal like roots, but Human like shape. This can possibly be fossil evidence of interbreeding and thus hybrid. They haven't checked the DNA yet, but there's prior art in modern human DNA that show some 2% coming from Neanderthal.
So the difference is we might now have fossil evidence as well as DNA that interbreeding was possible.
There's no proof of any explanation of why Neanderthal and Human would have interbred. Or if that is the single cause of pure bred Neanderthals disappearing. The discovery doesn't even make any claim to it from what I could tell.
Finally, there's a possibility the fossil isn't from a hybrid at all, but from some independently evolved specie or Neanderthal who developed Human like traits on their own. Though that seems less likely since they know the area the fossil comes from was connected to the rest of the continent.