> By arguing that your usage was fair use, you are admitting to copyright infringement.
No, its actually fairly common to argue both that an act wasn’t infringement but, if it was, it would be fair use.
One way you might do this is to argue that the thing copied was outside the scope of copyright, bur then argue that, if it was covered by copyright, it would be fair use.
That was, in fact, Google’s argument in this very case.