Why is O.K to interfere, terrorize and declare wars to Islamic & Catholic countries but not to Communist ones?

IF you think about Iraq was actually the right kind of place to try to setup a democracy and nation build given it has vast oil resources decent infrastructure and education. They just messed up the post war nation/govt building and security because Rumsfeld didn't want the Army to be a police force. That is why its taken this long to even get a consensus govt rolling.