When I heard first about the "fair use" being tossed around in academia when I was taking classes in college, I didn't know the whole definition but I knew the whole idea is that there are statues and limitations in regard to using someone elses idea, even if not being used fully verbatim, but even taking some chunks into your work and building on it, in academia the idea for "fair use" made sense since in college your proijects are not so intended for profit but for educational purposes.
The parallel example is like my college English class. Even though I don't verbatim copy someone's essay, just making quotes from another academic article and not citing it in my essay is considered forgery. So to have my "paper" in so termed, I cite my source proving that my work is not all my own.
However in context of patents and agreements, if one is to build profit from an original idea that has a EULA for developers when you download the JDK from Oracle and Sun, many do not technicaly go through the lengthy agreement in using other peoples software and the EULA agreement. However I am sure when in court, because Google didn't as they put "didn't have their paper" and it is so proven that Android has been a for profit software and I highly doubt they contributed anything back to Oracle, that's when these court issues do come into play.
Another example of this is someone who uses Visual Studio Community and in the agreement for use, they require that if your self company or small organization exceeds a profit amount, to buy a liscence for your organization. Would I be right to argue "fair use" in this instance when the company already stated its terms?