Comment by HelloImSteven

In the U.S. at least (obviously not the same everywhere), fair use doesn’t necessarily require your work to be transformative. It’s one of several aspects that gets considered, albeit a fairly significant one in many cases. Downloading books/research articles/pirated works in general wouldn’t be fair use as the purpose of the act (obtaining a book to read) directly impacts the market for the work (selling books). There could still exceptions in some cases, mostly related to teaching I’d imagine.