The negro is a native of tropical climate where fruits and nuts are plentiful and where clothing is not required for protection against the weather ... The essentials of society in the jungle are few and do not include the production, transportation and marketing of goods. [Thus] his racial constitution has been fashioned to exclude any idea of voluntary cooperation on his part.
We need to focus on that this was the DEMOCRAT party, and one branch of it. The GOP was more supportive of civil rights laws than the Democrats were, but the Democrats controlled both houses of Congress, and when it was passed in 1965, the Democrats got most of the credit.