People can be offensive to other religions. I have seen cases in which a crucifix was placed in urine as a piece of art, or a Bible burned numerous times. People have a right to do these things, so long as they don’t get someone, or cause serious property damage. As for everyone in the U.S., I would say that plenty of people would write on their blogs about how burning a Qu’ran was a good or a bad thing. IMO, if someone bought the Koran just to burn it, they wasted money, why not just write on a blog an argument against Islam?
As for liberals, I never understood how they spend their time trying to look good to them when the very beliefs they espouse (i.e. gay rights, secularism, etc.) are the elements which are among the most offensive to Islam, and many times more so to the openly radical amongst Islam.
That's their business, not mine.