First, making the assumption--quite likely false--that back when slaves got their owners' names some relative of Davy Crockett owned her fairly distant male ancestor. Yeah, it's possible, but since Wiki says it derives from "large curl" (of what sort, unsaid) why not have a few originators of the name when surnames was passed out in medieval/renaissance England; I have trouble thinking my surname was issued to one and only one male and his family).
Second, that it's deeply sarcastic, dissing her by saying how proud a prominent American 'hero' of some stature ('high IQ' in some way, but hey, the Stanford-Binet scale pales compared to emotional and whatever other kinds of intelligence, right?) when really he's saying he'd be deeply ashamed of her on so many counts.
Sarcasm is tricky. If it's perceived wrong--and who can predict that?--it's taken as an assertion. Trump uses sarcasm a lot, and if something comes off too weirdly you should think, "Hey, maybe it's sarcasm and my views and 'stance' don't like it." In other words, being flexible enough to adopt another, fairly foreign perspective.