I've known Chris for a few years now. During this time I've asked him many questions, worked with him on projects (open source and otherwise) and I have never seen him act the way you describe it here. Moreover, I've also seen him talk to and teach people at conferences. He has always been very patient and helpful, encouraged people and nudged them in the right direction when they were stuck. Of all the teachers I've interacted with throughout my life, Chris definitely fits in the category I want to learn from. Like someone else has mentioned before, I encourage you to provide constructive feedback to him directly, he cares about teaching and does want to improve.