personally, I don't find it hard to tell that kbuntu is under the same umbrella, since it ends in 'buntu'. I can't think of too many non-official spin offs that use that name.
Things are rarely just crazy enough to work, but they're frequently just crazy enough to fail hilariously.
It also makes sense to have a distribution called just 'Ubuntu' for people who are just getting started. Can you imagine what it must be like for someone who doesn't know anything about the Linux world (let alone Ubuntu) and have to decide whether he should get Gubuntu, Kubuntu, Xubuntu, etc.?
It's better to have the one 'Ubuntu' so newcomers have a starting point, and since the Gnome version is the "default" one, then it makes sense that this is the one that's used.
Yes it is stupid the way Ubuntu does it. You will notice that no other distro does it this way.
I first glance I though you really got a point. But Ubuntu itself is the tradmark, the word... all the rest are derivatives.
Why Coca cola wasnt called coca coca zero in the first place?
Ubuntu is a Gnome distro, why doesn't it make sense for their gnome version to be called Ubuntu?