Well, actually both statements are probably (and may be even provably ;--) true.

XML was developed by people from the SGML world as a way to capitalize on HTML's success and to re-marked SGML in a more "you-can-do-it-too" way.

So for SGML people (of which I didn't know you were one merlyn!) XML is the replacement for SGML, but it was really proposed and pushed as a replacement for HTML. And it is still widely perceived as "the future of HTML".

As I saw it once XML is "HTML on steroids", and conversely it is "SGML on Prozac".

The bottom line is that XML is whatever you want it to be, and I don't think beating up on people who see it from the HTML angle is a good way to promote it.