The greatest thinkers of the past have laid down the intellectual and philosophical framework for modern civilized society. Still, they committed atrocities such as owning slaves, supporting genocides, and having many other bigoted views. They are revered because they tackled social problems by applying principals and truisms to issues in ways that lead to solutions and created justice.
However, from a thought process perspective, what actually prevented these historical figures from applying these same principals and truisms to the issues in which they were so obviously bigoted and short-sited? Society can influence people to think a certain way, but it can't FORCE them to think a certain way. It can't FORCE them to apply a moral principal that they claim to subscribe to some situations but not others. So is it wrong to consider this a FAILURE of thought?
Could you say in fairness that these figures didn't truly understand the morals and philosophies that they espoused, since they failed to apply them in other obvious situations that led to human rights travesties?
Example: http://www.youtube.com/watch?v=sw-n9w3ImVk (What Famous Men said about Jews)