Dictionaries are not the only places you find definitions. E.g., the IEP has a dozen definition of concepts with "moral" in them, like "moral luck": http://www.iep.utm.edu/moralluc/

It doesn't have anything for moral rights used this way.

I think your google-counting approach is an ineffective way to get at anything. If you read the citations that come up from your suggestion, it's not at all clear that everybody's talking about the same thing. And some of them are definitely doing what I think seankimdesign: puffing up some other perfectly good concept by adding the word "right" to it to make it stronger.

So no, I definitely do not agree that the normal definition of "moral rights" is what you get when you subtract the actual normal definition of "moral rights" from the search results.