With all due respect I was using a touch of sarcasm there. Outlining how ridiculous the proposal of punishing the innocent is.
Any person threatening violent behaviour towards another should be removed. Problem solved. Removing the flag and leaving the violent person in place simply shifts the problem to another day when the person becomes 'offended' by someone else's actions.
You are inhabiting the US, you abide by their laws and benefit from their countries assets and facilities. You do not move there to gain all of this and then demand people already there change their ways to accommodate you. You can be as patriotic to your own country as you like, but don't you dare be offended when someone shows support for their country and you definitely have no grounds to complain of someone wearing the flag of the country you are inhabiting. If you don't like it, leave. If you are going to use violence to try and get your own way you should be thrown out.
I know it sounds exceptionally brutal but frankly I'm sick of this "we should accommodate everyone" approach being taken recently, especially in the UK. It is the current residents who are suffering because the government is ignoring what they want and going straight to the needs of immigrants.