So we shouldn't learn about a hidden part of history to stop ourselves from doing it again?
That won't stop us from doing it again, nor will it cause us to do it again. We have our own minds that are not controlled by our ancestors. Just because our ancestors did something atrocious doesn't mean that we will do it.
If we weren't doing it and had no intention on doing it before learning about this hidden part of history, then what makes you think that anything would change or be prevented after learning about it? We'd just continue to not do it (just as we were never doing it in the first place).
If for some reason we did end up doing it again, it would be for our own reasons, not pertaining to the previous incident. This is genocide we are talking about here! If a leader gets it in their mind to even consider something like that, then clearly their resolve is strong enough that knowledge of past conflicts has no effect on their current decisions.
Think about the concept of war itself. People have plenty of knowledge about the damage that wars cause. Yet that doesn't stop modern day leaders from starting wars and making threats.
Now I have a counter question for you:
Should we kill a toddler born in Germany in the year 2017 because Adolf Hitler carried out the Holocaust decades prior?