You throw out the term "moral relativism" as if it were some kind of insult, so I wonder what you think it means. At the simplest level, it's just the recognition that different cultures (and, by extension, different eras) have different moral standards. It's actually very relevant to this discussion, and I am pleased to acknowledge my application of moral relativism in this thread. I'd go so far as to say that you have to take a moral relativist position to properly debate the topic.
Your point regarding taking into account the opinion of the slaves is well made, and you're right to point out that it shouldn't be overlooked (however your assertion that they knew slavery was wrong is questionable as, for the freshly acquired slaves at least, it had long been a fact of life in their culture).
As for sweeping anything under the rug, that's just not true. I understand what happened and accept that it was wrong by the standards of today, but I don't believe tryng to right those now distant historic wrongs through legislation is either practical or useful.
I have to say that, as a UK citizen, I find the very concept of paying to make amends for historical events quite alarming (god only knows how much it would cost us!). In this matter, realpolitik rules.