Is this man making an obscene gesture? (for the answer check Dark Damian)
To be frank I missed it too. I did not know the gesture. Next time I will be more alert.
I think this sort of ‘vulgarity’ is perceived much the same was as insulting gestures. Some people are sensitive to it while others do not see it. That makes it easy to explain what happened here. Damian knows the gesture and appears to be a focused TV watcher (or at least with certain sporting events). Therefore the gesture that was intended as a shocker reached his eyes but not those of more innocent or less alert couch potatoes.