Does the museum have an ethical obligation to do the following? 1. Make the artist’s racist history, and apology, public at the show and in its publicity; 2. Allocate profits from the show to a program that benefits local Black artists; 3. Ask the artist to fund an art department in a historically Black college or university.
I think the museum may be wise to warn patrons that the content of the art is potentially offensive to people. They may also inform the viewers that the views and concepts expressed in the artwork may not reflect how the artist currently feels. They are a product of history, a sign of the times of when the artwork was created and based off of.
They may choose to provide as much additional context to the art as needed to ensure people are warned about what may be viewed as offensive these days. I see no reason to censor or soften the art though.
People do deserve the right of some content warning though; so that they may practice appropriate viewer discretion. Nobody needs their day ruined by unexpected racism, in a content context when they're not mentally prepared for it, and informed of the historical context in which it was expressed.
If the art otherwise stands out and expresses a worthwhile message; I think racism can be safely ignored by a prepared viewer who understands that the racist messaging is not okay by modern standards and is willing to look past it to see the other themes in the art work. I don't believe any museum of a respectable nature would present this art if it did not have some redeeming quality; as they're typically concerned with preserving our history. Hiding the darker facets of our history, such as racism, from our descendants will only ensure that they repeat those mistakes.
As for points 2 and 3; I think this decision should be left up to the museum and the artist as a whole. I wouldn't expect contributions to a charity to offset the harms; nor do I feel they would genuinely "offset" the racism in the art. Let the art stand alone, in it's darkness and it's light, separate from it's artist and the museum presenting it. Judge the art alone.
It is okay to dislike an art piece but still have learned something from it; or to appreciate parts of it's message but not others.