Yep, I’m aware. (I taught history for more than a quarter century. Lincoln understood that the Constitution did not allow him to touch slavery. But as CinC he could free slaves in areas actively in rebellion against the U.S.—depriving the South of an important asset in their war effort.
The Emancipation Proclamation carefully excluded Southern States (or parts of them) already under Union control—parts of LA, TN and VA are specifically mentioned. And of course slavery in states not in rebellion, MO, KY, MD, DE, & WV remained legal until either the states abolished it or the 13th Amendment took effect.
Up until that time, Federal law required the Union army to return runaway slaves to their Confederate owners, though many Union generals were very reluctant to do so. The runaway slaves were called ‘contrabands’.
You are right—December 6th is the true Emancipation Day. But as we’ve been told some people believe their ‘truths’ are more important than facts.
Having been a history teacher you likely know that the Royal government issued two emancipation proclamations during the previous insurrection.
Dunmore’s Proclamation, which offered freedom for slaves willing to take up arms against the Patriot rebels; and the Philipsburg Proclamation that more closely resembles Lincoln’s.
Had London won that war slavery in North America would have ended 90 years earlier.