You really need to read up on the constitution, and the process of the convention. There was a separate compromise concerning the slave states, known as the three-fifths compromise, as three-fifths of the slave population--60%--were counted for purposes of determining the number of Representatives a state would send to the House. It had nothing to do with the Electoral College, and the Electoral College had nothing to do with the three-fifths compromise.
The American constitution is a relatively brief document, written clearly in plain language, and accessible to any literate citizen. There are entire libraries devoted to the constitutional convention, and very few of those books disagree in anything but minor details.
It passeth understanding why Americans remain so ignorant of the bases of their government.
At the time of the convention, the most populous state was Virginia, a slave state, and it was a neighbor of Maryland, another slave state with a very large population. At the convention, the small states banded behind the leadership of New York and New Jersey--two states with relatively small populations. You know, 230 years ago, New York was not a bustling metropolis, and Virginia was not a bedroom community for Washington, DC, which didn't even exist at the time.
But you go ahead on and rant, you're invincibly armored in your ignorance. Another internet warrior who argues because he can, and not because he knows what he's talking about.