Sigh.
You question these people's wisdom because they are "white male slave owners".
Did you ever think that because they were confronted with the reality of slavery they were much much more attuned to the issues of human rights than say a tech worker in our society who doesn't notice that almost everything they use and touch was made by slaves? Who built that iphone? Sewed your clothes? Who mined the cobalt which allows your lithium batteries?
And even in the west, slave labor hasn't gone away. We just hide it in private prisons or "illegal" immigrants.
We are much better at tech than the founding fathers, but I have no evidence that we are any better at moral and/or political philosophy (and quite a bit of evidence against).