Those men may not really be Tibetan monks. They may have been hired to dress as monks and do bad things.
The world is a very confusing place!!
(Of course, I would not be surprised if they really were monks. Even men of great faith can be pushed to commit acts of violence if they are angry or afraid enough. Tibet's autonomy is being usurped by a very difficult foe, and that can be a very frustrating thing for a strong man to accept. Tibet once had a reputation for having a good military and for being tough fighters. It must be difficult for any Tibetan who is proud of that heritage to stand by and watch as China's rulers take their autonomy away, and they cannot even fight back.)
Thank you for your reply. I was unsure if they were real or not.