I am not a lawyer. My understanding is that lowering the value of the original work is an argument against a particular use being fair use. Which is to say th

I am not a lawyer. My understanding is that lowering the value of the original work is an argument against a particular use being fair use. Which is to say that Fair Use is not intended to further commercial competition. And that the purpose of copyright is to forestall commercial competition. Of course I could be wrong.