I think the problem is, that we tend to cherry pick our discussions in school in regards to race/religion. I used to be a history teacher, so Example.
In American Schools, ask a child"how many children died in the Holocost" Most will say 6 million Ask the same, "how many died in the Holodmor" and they will all say "huh"?
The time between both was less than 15 years. More died in the Holodomor, and in much less time, but few know what it is, and probably many here will google Holodomor
Lets ask this question again, about slavery.
Most children know America had slaves, but why do they also not know that Arabs were taking slaves in much larger numbers and much longer time period than the Americans? Or that Arab taking of European slaves (Ukraine, russia, balkans area) was also a VERY big deal, and again, not talked about ever.
barbary pirates too over 1 million slaves from Coastal europe, but nobody speaks of that. Why?
And the fact that Spain and Portugal took MANY more slaves than American did, but again, left to the side of any real discussion about the subject.
So, in some ways I agree with Freeman, that bringing it up, but only partially, we create a lot of friction, so why not shelf it all, or talk about it all?