It was accepted that the Founders believed in what the Declaration said about all men, slavery not withstanding.
It was the principles of the Declaration that led to the strong abolition movements in the new states and outlawing it in the Northwest states.
How about The Middleton Bros of South Carolina, signers of the Declaration of Independence, who owned one of the largest plantations in that state. Or...Thomas Jefferson, who had a black mistress, yet refused to free his own CHILDREN? Do you SERIOUSLY believe these men believed that ALL MEN ARE CREATED EQUAL? Their actions speak quite clear.
If you believe otherwise, I have a great piece of ocean-front property in Colorado for sale cheap.....:)