Was it appropriate for an airline to remove a passenger from a flight because he refused to stop praying and take his seat for takeoff?

In today's news it was reported that a passenger on a plane preparing for takeoff began praying in the aisle. When asked to take his seat for takeoff he refused, and his companion told the airline personnel that "once you start praying you can't stop in the middle". Despite the instructions of the flight crew he refused to take his seat and so he was removed from the flight by airline security. The passenger claimed his right to pray was paramount, while the airline claimed that they have a right to regulate safety and security on planes and a passenger out of his seat during takeoff could prove dangerous.

UPDATE: The passenger was not actually praying in the aisle, but was actually in the rear of the plane near one of the exits. But the rest of the story - that the passenger refused to take his seat and was escorted off the plane by security - is accurate. Sorry for the imprecision.