Because it's awesome? Who doesn't like the Wizard of Oz?
I don't really. I don't like old movies. I don't think it has aged very well. Plus it is full of annoying songs. I didn't even really like it as a kid. For me, pretty much the oldest movie I enjoy, is Easy Rider. Now THAT has a hell of a soundtrack.
I suppose most of you wouldn't enjoy the ultraviolent horror movies that I watch on a daily basis, or pro wrestling, or anime...
I DID enjoy watching the Wizard of Oz with Darkside of the Moon playing on an outdoors screen they set up outside of the student union of one of the schools I attended. That was fun.