Luckily Christianity never inspired any atrocities like the Crusades against the Jews or anything...oh...wait...yes it did. Do you tell your kids all about the Crusades? Just for balance, mind you.
I will when the time comes. Of course, Islam inspired the Crusades more than Christianity did by attacking first. But then there were some atrocities committed against the Jews as part of that, that were just wrong.
I'll will teach them that. I'll teach them about the Roman Catholic dark days when the leadership persecuted true Christians for reading the Bible. And other such things done in the name of Christianity. It's important for them to know that they must search God's word and pray and not just assume that because some Church leader is telling them something that it is true or right.
Acts 17:11 - Now these Jews were more noble than those in Thessaloni'ca, for they received the word with all eagerness, examining the scriptures daily to see if these things were so.