For molecularshyness :
Wasn't it the republican party that was founded in part on an anti-slavery platform?
Wasn't it the *republicans* who propped up Abe Lincoln and strongly favored ending slavery?
Wasn't it the *republicans* who championed civil rights legislation while democrats filibustered it?
The republicans support business because business (including businesses owned by blacks and other minorities) are the backbone of our capitalist economy which preserve our other freedoms. Hard to preserve anti-discrimination laws in hiring if there are no businesses. Hard to preserve anti-discrimination laws in property purchases if no one has money due to a poor economy.
On the other hand, the democrats support giving away the US treasury as much as possible to those they view as needing help from the government- and largely that has been people they look down upon as helpless or ignorant (blacks, immigrants, etc).
As I discussed in my previous post, freed slaves were mainly republican. It was only in recent history that the black vote migrated en masse over to the democrats- when democrats in the 60s started handing out massive portions of the treasury for social programs.