They are doing the biding of the jihadists by strongly opposing churches ad Christians. The jihadists want to kill Christians but when these suit and tie wearing Muslims attack them through speech, it's mission accomplished for Al Shaaab.
They're not worried about terrorism because their religion is full of terror and hate. Where do you think Al Shabab and ISIS get their hideous ideology from?
Al Shabab is instrumental to destabilize Somalia and has nothing to do with religion.