I think they are inherently the same thing and don't deserve multiple tags.
Breakdown of the tags:
These tags have been destroyed.
Based on @jacob and @njallam
This site is about Ubuntu, so none of these tags are needed. This is like having programming-language in Stack Overflow.
I think we should merge them. The people saying we should destroy them, what if the people are asking about Kubuntu, or similar distro's to Ubuntu. (I, personally, count Kubuntu, Lubuntu and all the other "untu" distro's as seperate fom Ubuntu)
Maybe their asking about the differences between Fedora and Ubuntu. These tags would apply. So, why destroy them?