"Love it or leave!"

I have to say, I don't understand this point of view at all. I don't understand people who act like you have no right to be in the country if you don't agree with all the same things as them, and mostl of the people I've seen who say it are the ones who bash the president or say that all Muslims and flag-burners should die. They say that 'our troops fought for your freedom!' but if you use that freedom in a way that they don't like, they think you should be physically harmed, deported, or worse, killed. I don't get it.