I think this is misleading.
I think when tossing out the credence of people such as Wadhington or Jefferson with the slavery problem, there is very little context understood about the cultural norms, science and religion those people lived in.
The problem was that they did not see other races as people as they saw themselves. They saw their lives and societies and thought of them as savages. They further justified their ideology with both religion (which was more unquestionable than say, global warming is today) and scientific racism, which did things like measure brain size of different races.
The slave owner like George Washington and Thomas Jefferson was in some ways like an extreme version of the modern liberal -- seeing the person of color as needing an authority to rule over them and provide them with things like welfare, access to education, etc.
This has nothing to do with justifying slavery or ignoring that extreme abuses occured with such institutionalized imbalance of power. What I mean to say is to not throw away the baby with the bathwater. Some of the Founding Fathers created the greatest society to ever grace the earth and they deserve some credit for their heroic bravery and ideas on liberty, even if they lived in a truly fucked up world and had trouble seeing past that.
Edit: downvote away, I guess