Google has removed that URL from their indexes so people can't find that link when searching Google.
The URL or content within has been removed from the website.
Why the differentiation?
Not all websites are in compliance with DMCA takedown laws. Usually they reside in countries where there is no enforcement of the protection of IP/copyright.
Unfortunately, there is nothing that can be done directly about the hosting of such content and subsequently taking it down.
So by having Google de-index these links the vast majority of people can't stumble into the content. They would be able to do so if they have the direct link to the website in question.