Other mistake: In season 4 episode 7, 'Brian the Bachelor'. Cleveland is sitting in a chair in a waiting room and is getting really nervous. Peter tries to help him by tying him to a chair and when that doesn't work, he takes off all of their clothes. Peter ties Cleveland's hands to the arms of the chair and then takes Cleveland's clothes off. He couldn't have taken the shirt off while Cleveland's hands were tied to something without untying him or ripping the shirt, which he didn't do.
Continuity mistake: The interior of the Griffins' bathroom changes color (from yellow to blue), when Chris first talks to his pimple.
Continuity mistake: When Chris is sitting on his bed talking to Doug, the squares on his quilt pattern get smaller. (00:15:05)
Continuity mistake: Just after Lois decides to get rid of Chris's pimple, the pimple changes position in relation to Chris's hair. (00:09:30)
Revealing mistake: When Brian tells Brooke "I understand", after he thought he was being rejected, his left ear disappears for a single frame.
Factual error: Quagmire spikes Brooks drink. She takes a drink and immediately passes out. The pill didn't even dissolve let alone get in her system long enough for her to pass out.
Answer: Mort is Jewish, and Walt Disney was said to be antisemitic. So it would make sense in a Disney universe all the inhabitants would share his supposed beliefs.