What have many historians ignored concerning the Founding Fathers until recently?

Americans in great numbers are rediscovering their founding fathers in such best-selling books as Joseph Ellis’ Founding Brothers, David McCullough’s John Adams and my own Undaunted Courage, about Lewis and Clark. There are others who believe that some of these men are unworthy of our attention because they owned slaves, Washington, Jefferson, Clark among them, but not Adams. They failed to rise above their time and place, though Washington (but not Jefferson) freed his slaves. But history abounds with ironies. These men, the founding fathers and brothers, established a system of government that, after much struggle, and the terrible violence of the Civil War, and the civil rights movement led by black Americans, did lead to legal freedom for all Americans and movement toward equality.

Answer the above statement is (true);