Your examples are just false memories. For it to be an example of the Mandela Effect there has to be a collective element to it. E.g., a quarter of the people who have been to Disneyland remember there being a coaster called Mickey Mouse Ears.
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Also, Eli Whitney being the black man who invented the cotton gin is another one. I've talked about this one with many of my friends and those who went through the same school system I did all remember it the same way: Eli Whitney was right there with Harriet Tubman and George Washington Carver on the shortlist of notable black figures that we learned about every February. There would've been no reason to teach us about the
white guy who invented the cotton gin during Black History Month or, for that matter, any time of the year, so I believe that one is easily explained as a school curriculum screw up. There's really no reason I would've even heard that man's name, let alone celebrated his "accomplishments" in school, if he was being presented as yet another white guy who invented yet another way to further exploit slaves. They were definitely teaching us that he was a black man in the late 80s.