Leftists and their pet useful idiots are lying when they say the Constitution claims black Americans only count as three-fifths of a person. During the time of the Constitution, the southern states wanted slaves to be counted for the purposes of representation and for that reason alone.
The argument to count slaves had nothing to do with empowering them but rather for gaining representation in Congress. The Constitution provides proportional representation, or apportionment, in the House of Representatives based on state population.
Today, left wing activists want illegal aliens to be counted in the census for the same reason.
The abolitionists and the northern states did not want slaves added at all. But the southern states wanted slaves to be counted fully. The northern states needed the southern states to form the union. In the end, the Three-Fifths Compromise was made.
The founding fathers agonized over slavery, which was deeply embedded in the economy for over a hundred years before they wrote the Constitution. After much debate, it was determined that slavery would be abolished, but incrementally.
The Three-Fifths Compromise hurt slaves, in that it essentially gave slave owners more power, not less.
It was a win-win for the southern states to count slaves so that they could gain the seats in Congress. While slaves were counted, it was their masters who enjoyed the representation. Since slaves could not vote, that representation empowered the slave holders, not the slaves, which is precisely why the southern states fought for it. The Three Fifths Compromise assured that there were more voices in the federal government to advocate for their cause.
Ask yourself: Why was it that the southern states were pushing for slaves to be counted for representation when it was the southern states who had slavery?