it becomes a real tricky subject when u start arresting people for making duas. If he went outright and told people to join Shabaab or something, u might have a point. But for a simple dua is quite ridiculous and violates all forms of freedom of speech.
First of all there, is no freedom of speech in Saudi Arabia.
Second of all, he can pray for Al Shabab in the privacy of his own home. That's fine. But when he uses his public position as an Imam to pray for Al Shabab, and thus tacitly endorses their actions, then that is unacceptable. The free world is fighting a war on terrorism. Those who use their positions of power and influence to support terrorism, in anyway shape or form, are open targets. I hope the U.S government either asks the good King and our ally Abdulah to either jail this man again or consider him as a candidate for extraordinary rendition.