Goomba Fallacy

The Goomba Fallacy is a type of hasty generalization where someone thinks of a group of people as holding two contradicting opinions, being "stupid walking contradictions."

Example

Someone who is browsing Twitter may come across some users who say that pineapple on pizza is good, but also see some other users stating that pineapple never goes well with cheese. This observer might make a hasty generalization that "Twitter users like pineapple on pizza, but hate pineapple with cheese. That's stupid, Twitter users are stupid..."

This observer has treated these people as a monolith instead of individuals with their own opinions.