I don't think there is anything wrong with mentioning the history of slavery to kids studying the Emancipation proclamation.
I'd just like to see equal attention given to other aspects of American history, such as the religious objectives of the Pilgrims, the reasons for the Revolution, and the philosophical basis of The Constitution.
Yea you guys would have loved the pilgrims. They fired the first shots in your imaginary "war on christmas". The Pilgrims were ultra orthodox jackasses that England was glad to be rid of.