>>122613344>Why do people say this character was a lesbian?
That's the painful truth of it all. Had Marcie never been introduced as Peppermint Patty's best friend (and subsequently never referred to her as "sir") there wouldn't even be enough there to make the false assumption. Peppermint Patty's sole and defining character dynamic would be with Charlie Brown, that being her unrequited love for him.
Marcie is constantly one-upping Patty intellectually, deliberately makes her feel insecure about herself (through "sir" and other means), and of course, is one of the primary obstacles preventing Patty from finally earning Charlie Brown's affection. There is actually a very passive-aggressive relationship between the two girls that is clear to anybody who's read the comic strip (pic related).
That being said, Marcie and Patty are still best friends and at this point would be worse off without one another.