Dirt Bikes and snow - a bad mix?

How is it that Dirt Bikers can enter both the Winter and Summer X Games? All that's required are 2 different sets of tires. I'm sure the snowmachine-bilers don't agree with this.
Forgive me for being one sided, but when one says Winter X Games, Dirt Bikes are not the first thing that comes to mind -- It's those dirt bag looking lunch-try hucksters that do (see below)

I) Joe Dirt does a no-footed backflip to one-handed landed nack nack superman tootsie roll with both eyes closed.


II) Tara Dakides, one of the hotter lunch tray huckers out there, will be in Aspen all week. Dirt bag; i think not. Road trip!


III) Joe Dirtbag -- Dooood, wassup Brah. Killer. Aight. Later man.