we waited until the mid 1860s to outlaw slavery.
Yup, the USA was later in outlawing slavery than European countries. The reason can be attributed to different political systems. And unlike in Europe, it was far more contentious in the USA, and partly due to slavery, a Civil War was fought, something that did not occur in Eurpoe.
But your statement made it appear (and is apparently being taught in American public schools,) that slavery ONLY existed in the Americas. As with your statement where you ONLY mentioned slavery in the Americas, public schools do the same thing, without any context, such as mentioning that slavery has been going on around the world for nearly all of human history. That omission fosters the assumption that ONLY America participated in slavery, which is something that the “educators” are more than happy to allow.
Mark