I wasn't talking just about reselling, I was talking about preventing the commercial use of technical curricula labelled as NC.
For some people it's less about the money and more about the desire to keep information and knowledge free. NC prevents commercialization of the product at hand. For something to be Gratis does not make it Libre, but for something to be truly Libre it must also be Gratis. Your equivalence implies a two way road where only a one-way street exists.
How is that selling and not requesting donation? Encouraging the sale of a product inherently puts limits on the product, even if it's also offered for free.
For instance: having a product that claims to be FLOSS, and then releasing code that is difficult to compile without proprietary libraries or impossible to compile on certain platforms, and then selling the precompiled binary at a markup. How is that OK? How is that not seen as gatekeeping the product? How is that not putting a barrier to the product that is antithetical to the Libre manifesto? (Specifically the taking of creative work and turning the work over to profiteers)?