Honestly, I think it ought to be a national holiday. Call it Emancipation Day, and make it By G-d on June Nineteenth for the historical significance, not "On the Monday preceding it" as has been done with other holidays.
I agree it ought to be celebrated, along with well-publicized reminders of which party ended slavery, and which one propagated it, and started a Civil War to maintain it, and resisted its abolition after that war, lynching blacks along with white Republicans during reconstruction.