Interesting, but not surprising. I will say if you watch the entire episode of the program you will come away with a completely different impression of Burton’s reactions.

Even though I have zero agreement with him politically, he starts out the program saying he knows nothing about his family history. The program is full of emotional revelations for him.

The editing in this clip makes him seem angered to learn the truth, but his initial reaction takes place a few minutes before what we see here. It was just a simple “Wow” then a joke that Kunta is part white.