As much as I sympathize with your argument, we still have to look at the context of his filming. He isn't just filming skier friends for shits and giggles and for his own enjoyment. He is filming good skiers and puts out a product which he is paid for. Yes, he is young and it makes me extremely jealous haha. But nonetheless he has high quality work and so he has the right to turn projects down, especially in light of school duties.
Plus, if it were his close friend who wasn't even good at skiing, I'm sure he would film him. Just the context of the situation doesn't pan out. Sadly, this kid wasn't even asking for DTF, but this thread is interesting to see the perspectives of filmers, etc.