Their rudeness matches their size.
3 seconds sound clip from the It's an Adventure, Charlie Brown movie soundboard.
You can hear this line at 00:28:45.181 in the Blu-ray version of the movie.
Quote context
[...]
- One of their players licked me on the nose.
- Charlie Brown, what are you doing here?
- You're the coach of this stupid team?
- We can't play them. They're too little. We'd step on them.
- Are these people your friends, Charles?
- Their rudeness matches their size.
- You should come home, Charlie Brown.
- Are you an escaped criminal, Charles?
- When I grow up, I want to be just like you, Charles.
[...]