Nothing will change the fact that on that day, July 4, 1776, blacks in America were not a free people as slaves under the brutal treatment of rich white land owners. A quick search reveals:

George Washington owned more than 200 slaves
Thomas Jefferson owned more than 100 slaves
James Madison owned and sold slaves all his life
James Monroe owned 30-40 slaves
Andrew Jackson owned about 160 slaves
Martin Van Buren owned at least one slave
William Henry Harrison had several slaves
John Tyler had slaves
James K. Polk had 15 slaves
Zachary Taylor owned more than 100 slaves
Andrew Johnson owned 8 slaves
Ulysses S. Grant freed his slaves

Still. As someone mentioned above, Rock’s statement is partially satire with a large tinge of high irony and historical reality.