Of course not. Patents are simply a form of intellectual property, and Linux doesn't get a free pass.
OK - you know you and MS sound a bit like John Kerry. He's always going on about how what the Swift Boat Veterans said was untrue, was defamatory blah, blah, blah.
OK so have at it in court.
Someone who's always saying he's going to sue you and then doesn't is either very indecisive or doesn't have much of a case. Usually, of course, it's the latter.