“I know why the caged bird sings”
because you put it in a cage, dumba**. If it wasn’t in a cage, it would be in the forest where you can’t hear it.
It was NOT Maya Angelou who came up with the remark: “I know why the caged bird sings”. It was another authoress, Maya Angelou just “lifted” it and gets all the credit for the remark. I think Maya Angelou “borrowed” that remark for one of her books but never credited the authoress she took it from.