I think this point of the argument has been unfortunately lost in the kerfuffle over whether charging for apps (or app installs, to split hairs) is a viable business model.

It should be fine for a developer (or musician, or other creator of content) to charge for their wares. If the app being available really is valueless or if the prospective customer doesn't believe it's worth what's being asked, they are free to move along and select a different product or to develop their own. I'm not sure why this concept is so looked down upon.