Great, now they are blowing up people in cafes. That will make the Iraqis REALLY want to support their cause.
al-Qaeda doesn't want Iraqis to support their cause. They want Iraqis to have no faith in the Iraqi government and put their faith in militias, which would lead to a failed state and civil war in Iraq.
If suicide bombers were rampant in my city, I'd avoid crowds. You'd think these poor folks would exercise just a little common sense and not gather in groups becoming targets for the bombers -- I just don't get it.