The article forget one key point....
Iraqi government television said the *****Defense Ministry had approved the demonstration, a sign of the public anger over Israel's offensive in Lebanon and of al-Sadr's stature as a major player in Iraqi politics*****.
There is formal Iraqi government support for the demonstration. That upsets the whole "tiny minority" argument.
Not neccessarily. Unlike the days of Saddam regime, the Iraqis now have certain freedom of speech rights. I'm sure the US gov't would approve such a demonstration in the US, and I'm equally sure there would be plenty of DemoRats and Isolationists who would join in!