“We can’t just choose to learn what we want to know and not what we should know,” President Joe Biden said Tuesday from Tulsa, Oklahoma, on the 100th anniversary of a targeted massacre of Black residents there by their white neighbors. Dozens of people were killed in the attacks, hundreds were hospitalized, and thousands were held hostage, some for days. More than 35 square blocks in the wealthy Black community were destroyed. Yet many Americans know little, if anything, about the events. They were never taught.