But because of the fear of lawsuits, he would have to give him the loan.
Normally, an employer can tell when a black person is not able to do a certain job. In such a case, he would not hire him. But then there is the real possibility of being sued for discrimination and losing his entire company. So he hires the black, and puts him in some position in which he hopes the black will not do too much damage to his firm.
You multiply the effect of this several million times, and you get the story of the failure of the American economy.
It makes me wonder about the wisdom of the Civil War. After all the American Constitution is in its essence a contract that the Northern States were unilaterally trying to change. This is in general not how contracts work. The normal way a contract works is that after you sign on the dotted line you can't change the terms without the consent of the other party. This is clearly what the North was doing and so by definition of contract it justified the secession of the southern states.