You do understand that to say "I said what I said" does not make it true or factual, right? You have a right to a judgement that they were treated as if they were not Americans. And, that judgement, IME, is cogent and entirely true – and it makes slavery a national crime against American citizens for which reparations must be made.

However, no one has the right to claim that incorrect or false facts are true. "Alternative facts" are NOT a thing. Facts must be repeatably provable by other sources. Your premise is flawed because the evidence proves it is incorrect… it is false.