Evidence that not all of these thugs are about following Islamic law and jihad. They only want power and use Islam as a front.
That is not to say there aren't many who kill for Islam and for jihad but they, too, want power and control - over everyone.
You're not getting it. The judge was killed for being an apostate, for NOT following Islamic law.
It is the PIRATES who are faithfully following Islamic law, waging Jihad against infidel shipping, and collecting jizya from the infidels. By punishing Muslims for following Islam, the judge became an apostate, and was liable for being killed by any Muslim with the opportunity to do so.