A special kind of idiot who believes that all people who hold a different view from oneself have the same views as each other.
Coined by Dilbert creator Scott Adams on his blog to give a name for people who believes there are only two viewpoints for every topic. (Don't worry, you're not being a labelass if you use this term.)
Person 1: "I don't think we should bomb Elbonia just because someone said they have a giant slingshot."
Noun - As in sexism or racism, binarism refers to a collection of harmful thoughts, actions, laws, and other social systems that uplift one group of people while erasing or otherwise harming a minority group. In the case of binarism, the word refers to actions and thoughts that promote the gender binary (male/female) while excluding, erasing, or otherwise harming people of other genders or no gender at all. People harmed by binarism are generally people within the nonbinary gender umbrella, or agender. Binarism is often exhibited towards nonbinary people by cis gender and binary trans gender people alike.
The adjective form of binarism is binarist. A specific thought/action/etc that exhibits binarism is said to be binarist in quality.
I wish people would say "honored guests" instead of "ladies and gentlemen" when addressing groups. "Ladies and gentlemen" is so binarist! It makes my heart hurt just to hear it. I really wish binarism wasn't a thing, and that people like me were recognized as being real.