While your observation is undoubtedly true, there is more to the story. A sin always gives the opposition a weapon, and as the full text of the Medved article makes clear, the US moved swiftly to wipe out slavery, and later, Jim Crow (although not fast enough, but, in comparison with other nations, faster than any other nation).
The more I read, however, the more I see that the fight of good vs. evil has been weaponized on the left by any transgression whatsoever on the right. Organized socialism and communism have been behind not only so many of our social ills, but also behind the perception of our motives, trumpeted in the press, and the calumny of false "solutions."
I recommend to any of you interested in our current dilemma to get a copy of a long out-of-print book entitled The Fabian Freeway by Rose L. Martin. It is a history of the socialist movement within the United States and Europe. As you can see, the Fabian Society, of which Tony Blair is a member, long ago succeeded in socializing Europe. This evil of anti-Christian social engineering has made Europe easy pickings for Muslim infiltration and overthrow.
We really must understand that the left wing will say anything and tell any lie and use any "shame, shame" device to weaken the right, the open, the transparent and the truthful history and institutions in this country.
I have read that book (it is in my University’s library). It is a good read.