i would imagine that it partly began with edits using rap/hiphop. the beat is generally heavier and makes for a more exciting edit. from there kids starting listening to it while skiing and it kinda just snowballed. it can be argued that the tall/baggy fashion is totally independent of the music. there are trends in ski fashion just like there are trends in street fashion. a lot of it has to do with what the pros are doing. we all are bound to hop on the bandwagon at one point or another.
in the end everyone is entitled to their own style and music preferences. just do your thing.