I don't do this very often, but I'm going to pull rank.
As the world's leading critic of all things Canonical...
I really don't understand why Canonical gets picked on for this particular issue of high level branding. I've probably engaged in it as well at some point in the past. And to the extent that I've done it or encouraged other people to do it, I apologize. On examination, it's a highly irrational and subjective criticism which has been shown cannot be fairly applied.
For example Debian currently doesn't list "linux" on its top level homepage and bills itself as the universal operating system. I don't see the hand wringing over that choice of branding. Not everyone is thrilled with the complexity of Debian offering bsd and linux kernels, but noone is really making it a point to beat them up about choosing to downplay their important role as a "linux" distribution ecosystem.
So with that said, what I believe is happening is that such criticism is generally misdirected frustration over other aspects of the Ubuntu/Canonical/community relationship that a person is having trouble identifying and communicating.