It's a list of historically underrepresented characteristics, and membership in one group does not imply membership in all. "Tall, dark, and handsome" doesn't mean everyone tall is tan.
Probably should have just said POC in my parent comment to skip all this side discussion, but the repetition is the point. - it's used for emphasis.
From wikipedia:
"The term aims to emphasize the historic oppression of black and indigenous people, which is argued to be superlative and distinctive in U.S. history at the collective level."
> "Tall, dark, and handsome" doesn't mean everyone tall is tan.
Correct, but everyone who is tall, dark, and handsome is dark. The person you're replying to is asking: don't "black" and "indigenous" fall under "POC", since POC basically just means "not white"? Or at least black should fall under it.
Black, indigenous, (and/or) people of color.