The images — men on horseback, appearing to use reins as whips to corral Haitian asylum seekers trying to cross into the U.S. from Mexico — provoked an outcry. But to many Haitians and Black Americans, they’re merely confirmation of a deeply held belief: U.S. immigration policies, they say, are and have long been anti-Black. The Border Patrol’s treatment of Haitian migrants, they say, is just the latest in a long history of discriminatory U.S. policies and of indignities faced by Black people, sparking new anger among Haitian Americans, Black immigrant advocates and civil rights leaders. They point to immigration...