Probably also has to do with how incredibly mean kids can be on this site.
The guy posted edits, got hated on, had some shots with L1P, got hated on, showed some of his video work to NS, got hated on... There are people who supported him the whole way through, but I'd conjecture that he left because he didn't really want to be involved in an industry that expresses itself in such a negative way online (and lets be honest... the freeski industry relies heavily on the internet for its media, advertising etc).
I would never post any of my creative work here, the positive feedback I might get wouldn't be worth the negativity in my opinion. Newschoolers really makes me hate skiing sometimes. I just wish people were a little more compassionate. Seriously lack of empathy around these parts, I'm no role model but I try not to say anything unless its constructive.