I'm saying that a statement that black people 'were treated unfairly' 'not so long ago' implies a basic ignorance of the way black people still are treated, that in general it is better not to make statements about things one knows nothing about, and that especially one shouldn't make blanket statements about subjects one is ignorant of when those subjects are hugely emotive ones.

"I was trying to demonstrate how people often skew their perception of truth to avoid coming to beliefs that appear socially unacceptable." Except that firstly, that was a side-issue to your main point (such as it was), that knowing the truth won't cause us to become immoral. Secondly, it doesn't make that point because, as you point out yourself, the truth in this case is that there doesn't appear to be a link between race and intelligence. Thirdly, the point you claim to have been trying to demonstrate is only really made in the paragraph about Gould, not in the rest of the paragraphs on race, which come from the premise "what if black people were intellectually inferior -- how should we treat them?", and go back to your main point.

All those paragraphs about race relating to your main point could have had any other example to make the point, and the point about Gould could equally well have used any of a thousand other obvious examples of people (consciously or otherwise) distorting results.

And, of course, your hypothetical "what if the racists are right?" question doesn't even lead to the conclusions you draw from it. If it could be shown, for example, that black people could never understand basic political questions, it would be entirely rational to at least consider removing the right to vote from them. Saying "An outcome where a particular race becomes less happy could only arise because the science was not properly understood" would be outright false, in that case.

And as for "What's obvious to you isn't necessarily obvious to all readers", I think that the obvious parts of this post would be obvious to anyone who's spent any time at all on this site.