It wasn't a general purpose term when it was coined. That only occurred later, as companies jumped on the bandwagon while not actually permitting the user freedoms that are goal of open source software.
(There's a side argument of whether "Champagne" should be a protected term. The physical region has clear boundaries, but that doesn't mean that the beverage should be defined in terms of the region. If I am opening a combination diner/antique shop, I may advertise it as "Hamburgers and China", even if I am neither near Hamburg nor China. I do not need to follow the lead on calling champagne "sparkling wine" and name my ill-conceived business venture "Ground Beef Patties and Exquisite Ceramics".)
