So I can imagine and understand someone not knowing it
That might (at a stretch) be a fair comment if that someone was like you - not media savvy, not particularly aware of current events (you said yourself earlier that you don't watch TV or listen to the radio), completely unaware for whatever reason of the historical links between monkeys and racism. DB is none of these things - you're imagining something of someone who is well aware of the above in order to excuse his behaviour.
"My Kid Had to Unlearn Everything America Taught Her About School"


) That is his way of thinking , not mine!

