No, only people that object to freeing the slaves would say that. It is culmination of Lincoln’s Emancipation Proclamation, marks when that action finally reached Texas. We should celebrate this just as equally as we do Independence day. And this should be a Republican-led holiday.
Even if the Republicans did lead it, the media sure wouldn't portray it that way. Remember this only became a Federal Holiday because somebody noticed Trump had a rally scheduled on it. Before then, few outside of Texas had even heard of Juneteenth.