"Moslems have a duty not to spread their faith by converting...but by killing those of other (infidel) or no faith, according to THEIR teachings."

Now that is a dangerous misreading of Islamic teachings. I'm sure you could find Moslems who think or act that way, as you could find Christians or Hindus or even some Buddhists. But in all these cases people thinking that way would be way out of line, and in conflict with the central tenets of the religion.