I demand that you show clear evidence a factual basis for your claim for I consider it vile calumny.
The clear evidence is that he owned hundreds of slaves, and that he bought and sold human beings as chattel property. It doesn’t get any clearer than that. He also acted to apprehend his runaway slaves and signed the Fugitive Slave Act of 1793, which created a nationwide enforcement mechanism for apprehension and return of slaves to their rightful owners and punishes any who would assist fugitive slaves.
It would be a vile calumny to assert that Washington was morally convicted of the evil of slavery but nevertheless engaged in the purchase, sale, possession, and apprehension of slaves.
Washington did became morally conflicted about slavery in his later years. Washington did nothing to advocate abolition publicly, though he did privately mention his desire for a phase out of slavery. Washington willed the emancipation of his slaves after he and Martha died. Big deal: actions speak louder than words, even those contained one’s final testament.