tl;dr: all you endemonised Protestant Anglo trash can go back to England, for all I care.
Half of the problem is that people these days tend to judge historical figures by current standards of behavior (when it suits them) which is why Columbus and Cortez get slammed for being vile enslavers and crushers of native cultures while those Native American Nazis known as the Aztecs get a complete pass for doing much the same thing, only with human sacrifice on top. To say this is dumb is a monumental understatement, and the dumbness was recognized as such by historians way back in the 1940s, if not earlier. I will grant you that Columbus gets a lot more credit than he probably deserves for "discovering" America, and it is true that until the end of his days he was convinced that he'd actually found Asia. As if any of his critics, in that time and place, would have known any better. Still, this mindless adoption of discredited slurs from decades past does no credit to the Oatmeal or the people who are apparently relying on it as a counter to the saccharine portrayals of Columbus in their childhood history books.
There is a reason we don't inflict Samuel Eliot Morison and other great historians on elementary school kids. They're too deep; they cover the subject in so much detail that you could (for example) teach a year-long course on Columbus and his voyages (and his short, unhappy tenure as colonial governor) from Morison's Admiral of the Ocean Sea: A Life of Christopher Columbus. Unfortunately, your average high school history teacher doesn't have time to go into that much detail, and just hits the high points: instead of explaining that Columbus opened up the New World to the Spanish Empire, it's just simpler to say that he discovered America and move on. Same with a bunch of other people in our history. It all depends on what the local school board thinks is important. In a lot of places, they go on about Leif Ericson, despite the Norsemen never actually colonizing Vinland and in fact, not even managing to keep their toehold in Greenland*. This is why you hope to instill a love of history in kids, so as they grow up they can go look into these things at their leisure and at greater length, preferably with the help of people like RAdm. Samuel E. Morison, USNR (Ret.), Winston Churchill, Alistair Horne, and others.
In the meantime, pause for a minute and reflect that without Columbus, there would have been no Spanish Empire in the New World, and very likely no English or French presence either. Which means most of you reading this wouldn't be here, either. Which means you'd be living in a world described by George Alec Effinger in Relatives, which sucks pretty badly.
*I don't want to hear any of your whining about global cooling.