This sure makes it sound to me like he was more concerned with the civil rights movement of the 1960s than with the copyright status of his speech in 2025.
EDIT: Come on, downvoters — do you really mean to suggest that King would have wanted a civil rights memorial to have to pay out his family before it could celebrate his cause?
"King himself donated proceeds from licensing the speech to fund the civil rights movement"
This sure makes it sound like he wasn't ignorant of copyright law and its impact on his speeches.