I am guessing the OP is in favor of Juneteenth.
I invite anyone interested to read the raw, unredacted text of the 'Emancipation Proclamation.' Among other tidbits, the author specifically excluded from scope all Union Slave States and Commonwealths, as well as (for some reason) the counties and parishes proximal to Norfolk, VA and New Orleans, LA.
Thus, it is an historical fact that, after the Emancipation Proclamation went into effect, there were Yankee Generals who still, quite legally, owned slaves in the United States. Also, since the Confederacy was a separate country at the time (how many Confederate citizens voted for or against Lincoln in 1864?), Lincoln had the same legal authority over the areas he specified that I do over Laos.
While I applaud freeing the slaves of Texas - Texas seceding from Mexico and being amongst the United States specifically because Mexico forbade ownership of human beings (come to think of it, I don't recall the U.S. supporting Mexico's attempt to quash the secession of a state to enable slavery) - after June 19th slaves in Missouri, Kentucky, Tennessee, West Virginia, Maryland, Delaware and the aforementioned portions of Virginia and Louisiana were still slaves.
It wasn't until the 13th Amendment was ratified and signed on 06 December 1865 that the slaves in the areas specifically omitted from the Emancipation Proclamation were freed.
I view slavery as repellent, but see our revisionist view of the subject to be an exercise in ignorance.
BSBD,
Winsor