that many of our founding fathers who did own slaves found the institution of slavery inconsistent with the foundational ideals of the new republic. The economic reality of slavery, along with the established social rigidity of the day, helped them rationalize continuation of an institution they new was not in keeping with the notion that freedom is a gift from God to every human being.
So, some did stand up and say "This isn't right." Some very important people did that. But, they didn't do it very loudly. And their actions most certainly did not match their words. Perhaps the most striking example of this was the fact that Washington's instructions in his will were to free his slaves (his only, I might add) upon his death. He found the institution repugnant. But, he sure didn't do it in his lifetime. </p>