Were the Founders really pro-slavery?

The Foundry relays more facts about our Founders you won't learn in school these days:

On this day in 1787, the Continental Congress passed the Northwest Ordinance, which established the first official U.S. territory. Together with the Constitution and the Declaration of Independence, the Northwest Ordinance is one of the four “organic laws” of the United States and, as such, is critical for understanding the Founders’ actual views concerning slavery.

The final article of the ordinance declares unwaveringly that “there shall be neither slavery nor involuntary servitude in the said territory.” By a firm majority, Congress had officially repudiated slavery. Significantly, the resolution caused five states to enter the Union as free states (Ohio, Indiana, Michigan, Illinois, and Wisconsin). Furthermore, the ordinance was reaffirmed by the newly created U.S. Congress in 1789—two years after the ratification of the Constitution.

The Northwest Ordinance reveals that, despite the compromises they made to preserve the Union, the Founders were firmly committed to immediately halting the spread of and eventually eradicating the institution of slavery.