I don't think the scenarios are all that similar. The first is about taking a precise and full replica of a copyrighted work and putting it on a file sharing s

I don't think the scenarios are all that similar. The first is about taking a precise and full replica of a copyrighted work and putting it on a file sharing system. The second is about borrowing, perhaps heavily, from a copyrighted work to create a derivative work. I don't think it's necessarily inconsistent to consider the first infringement and the second fair use.