Authority on the subject? I think not.
To argue that Slave families were kept intact is using a very narrow sense of what we mean when we say FAMILY. Families choose to live with each other, they do not endure their loved ones raped and bred like cattle, or sold off like so much produce. Families protect one another, and Slave families could not do that, because guess what they’d want to protect them FROM? Slavery! So even if some professor can claim that Slave families were kept intact, due to DNA records or some such tripe, the meaning of the word family must be distorted in order to fit the claim.
Good thing you weren’t in college in the 1960s, since you believe the student disrespected the teacher in this instance.