While it's true that you're not responsible for your ancestors' actions, you usually have similar nature and nurture to your ancestors, so it's useful to take them into account when attempting to predict your behavior.
No, that is wrong, and ironically enough considering the parent post I originally replied to, dehumanizing. It's important to treat an individual as an individual. No attempt should be made to discriminate based on someone's ancestors. Nepotism is also bad.
Edit: Changed "replied to" to "originally replied to".
I'm making a statement about predicting behavior; you're making a statement about ethics.
Since we've moved into philosophy, why is it important that everyone be treated this indiscriminately? Veil of ignorance? Couldn't it be valid to protect the community from the risk that the bad behavior is heritable (genetically or socially)?
Edit: Changed "replied to" to "originally replied to".