Owning slaves didn’t seem to keep the colonists from fighting for liberty and the right to self determination. And there were slaves in every colony at that time.
The Founding Fathers recognized that slavery was incompatible with the new nation created in 1776. They were unsure exactly how it could be ended. It was no coincidence that the anti-slavery movement sprang up in Europe as well as America after the American Revolution. The Confederacy was an attempted counter-revolution against the American Revolution, (read Stephens’ Cornerstone speech.) The slave owners were not believers in states rights or individualism, rather they wanted a more powerful national government that would enforce human slavery in every state.
And the founders put slavery on a path to extinction. Slavery in the US colonies was established by the British government, for British advantage.