Too funny, Peter!
I think that behavior is totally inappropriate, and I can understand why someone would not want to say something while it was occurring. In fact, you would probably be too shocked to even comment. However, it is not the airline's fault that this man chose to do this while in public.
It does arise concerns about those blankets. I have always wondered about those, and I bring a coat so I dont have to use them. Word up on the blankets----only use them when they come directly out of the plastic bag.