I'm astounded at how brave both Rushdie and Rowling. Especially Rushdie, of course, because as a PP pointed out, other people associated with his book have been murdered. There are plenty of Islamist fanatics out there willing to kill people who think the wrong things.
But I don't think I would even have JKR's courage. She's had thousands of death threats, and we know these people can be violent. You only need one determined TRA lunatic to carry out the threat. And yet she persists. Amazing woman.