As long as there's a monarchy, there shall be slavery. The two flow from the same principle: authority and ownership over other human beings. Attempting to salvage one while destroying the other will end only in disaster. First the monarchy, then slavery.
I'd like to see you try and tell that to an
actual slave. "Hey, dude, I'd love to help you break your chains of bondage and oppression and stop getting whipped daily, but I'm in even worse shape than you because I have to pay lip service to this well-nigh powerless ceremonial figurehead who doesn't actually whip me or anything, but it's just like slavery anyway."
The claim that constitutional monarchy is not just equivalent to chattel slavery, but the
more pressing injustice, is one of the most patently ridiculous things I have ever heard. Where's your priorities and perspective, man?