I just find it weird. Putting up a tree and decorating it is part of the Christmas tradition. It has nothing to do with the other holidays. Calling it a "holiday tree" isn't being inclusive; it's being stupid.
No, it's being accurate, considering the practice of bringing an evergreen into your house around the winter solstice is pagan in origin. It's just another pagan tradition Christianity adopted (such as the very notion of celebrating Christ's birth around the winter solstice.)
This reasoning is starting to get really old. How many pagans do we have these days going around having Winter Solstice celebrations? I'm not going to do the research, but I'm guessing we have a hell of a lot more people in this country celebrating Christmas. The tree, regardless of its origins, is now Christmas tradition.
I guess calling it a holiday tree is technically accurate in that it includes people who celebrate Christmas as well as, ya know, those random pagans that people keep talking about. I'm glad we're being so inclusive. Wouldn't want the pagans to feel left out.