If there was a giant cover-up then it was probably the poorest one in history because literally everyone I've ever talked to has heard about America's issues with things like the slave trade, the natives, their oil-wars, whatever the fuck went on in Vietnam, and, to a lesser extent, the various things involving the sex slave trade, drug trafficking, school shootings, whatever the fuck went on in Guatemala and those countries...
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I'm not sure what history books you're reading but you definitely picked up the wrong one
Most Americans can acknowledge that our history has been full of fucked up shit, but work to make things better in the future and not hate ourselves for things we didn't do
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I'm not sure what history books you're reading but you definitely picked up the wrong one