WASHINGTON — President Joe Biden on Saturday told graduates of a leading historically Black university that American history “has not always been a fairy tale” and that “racism has long torn us apart.” But on the nation’s best days, he said “enough of us have the guts and the heart to stand up for the best in us.” As Biden spoke, more than a dozen cap-and-gowned Howard University students stood with their backs to him holding handmade signs in silent protest over what they said were many forms of white supremacist violence. In his speech, Biden described the 2017 white...