Some of this isn't quite completely accurate, but funnily enough some of the inconsistencies match up anyway. For example, Big E full well believes in the gods because he knows they exist for a fact, they've been knocking on his doors for centuries. He just can't let anyone else believe in the chaos gods because they're literal infohazards. Likewise PBub knows of and frequently makes use of magic via Marceline and Peppermint Butler, but prefers science and doesn't want magic to get out of hand in her society.

Also PBub totally enjoys being worshiped as a god. She had a choice to give her people intelligence and didn't. Whether that was for the better or not is a minefield of an ethical question but the fact remains that instead of a society of complex individuals she created a society of easily managed simpletons that must look to her for caretaking. At least when the Emperor created life he created proper badasses that went out and fucked shit all up everywhere and made their own marks on the galaxy.