Yes, Greed is a devout Christian who also practices and BELIEVES in Scientology. He insists there's no contradiction between the two, regardless of what Christianity says about having one true and Holy God. I put believes in all caps, because we have argued with him ad nauseum that it is a belief system, because he says it's not, and that it's not required to believe in Scientology in order to practice. Further, Greed also denies that Scientologists (on the highest levels) believe there is/was an alien god named Xenu, and it had citizens of the planet flown in aircraft to Earth to be dumped into volcanoes.
Greed is basically just an asshole. He wants to disagree with everyone and go against the grain to draw attention to himself.