I think their concern was more the official endorsement of the practice of treating humans as private property, in contrast with a number of amendments providing individual rights (aforementioned property excluded).

They should have made that clear since the complaint reads as being largely about the 3/5 part.

Very strange that you went that direction instead of the more obvious "if slaves are property then they don't count at all".

I'd count them negatively personally but the grade school arugment made there has to die, the people who wrote that did so with the hopes of abolishing slavery in the future. It's exactly the opposite of how it is framed.

> You would've granted slave owners more votes?

I would have not had slaves.

That's really rich coming from a proponent of federal authority/power.

The alternative here was the articles of confederation or nothing and the states go their own ways as countries, not some fantasy in which the southern states torpedoed their own economies out of some love of the nation.

The constitution and the included 3/5ths compromise most certainly brought about the end of slavery much faster than taking a hard line circa 1790, or anything else that tipped the scales away from the united states forming a national identity would have.

You can say "this was the compromise they had to do" if you like. It's not even a bad argument.

You can't pretend it's not contradictory, though, in a document talking about rights and liberty, and that was the question posed.