Again, why would Blacks in, say Indiana, want to emigrate in great numbers to say, Louisiana?
Indiana Constitution of 1851
Article 13 - Negroes and Mulattoes
Section 1. No negro or mulatto shall come into or settle in the State, after the adoption of this Constitution.
Section 2. All contracts made with any Negro or Mulatto coming into the State, contrary to the provisions of the foregoing section, shall be void; and any person who shall employ such Negro or Mulatto, or otherwise encourage him to remain in the State, shall be fined in any sum not less than ten dollars, nor more than five hundred dollars.
Section 3. All fines which may be collected for a violation of the provisions of this article, or of any law which ay hereafter be passed for the purpose of carrying the same into execution, shall be set apart and appropriated for the colonization of such Negroes and Mulattoes, and their descendants, as may be in the State at the adoption of this Constitution, and may be willing to emigrate.
Section 4. The General Assembly shall pass laws to carry out the provisions of this article.
Now, back to the original comment that it was "only" after the South "resisted" change that Congress had to act. That's funny. The remaining (non-seceding) Congress wasn't going to act to force themselves to accept the Blacks. You are right, the racism was pervasive, but that wordy by itself doesn't clarify how it operated in "reconstruction."