Well of course they did. everyone knows and its well known where a lot of the labor came from but AOC is up there screaming like its discovered now for the first time and Amercans are ignorant of the contributions from the Irish, Italians, Chinese, Black Americans etc.... theres not a person today who hasnt read about this and been taught this in school... and its constantly reminded... so you have to excuse us thinking people when we realize that what we are hearing is pandering. It's not her facts that are wrong so much as the style and intention of her speech.
At the end we get the real direction when she mentions hispanics and she's trying to invoke the image of illegal immigration being ok. It's a political speech not a history lesson.