Why did presidents Roosevelt, Taft, and Wilson do little to improve race relations during their presidencies?

Almost no President from Andrew Johnson to John F. Kennedy did anything to improve race relations, because blacks were often prevented from voting (especially in the South) and the Federal Government Politicians were more interested in appealing to white male voters than to nonvoting blacks. It took LBJ and the Rev. Martin Luther King Jr. to finally get around to passing major civil rights laws in the 1960s. There were a few civil rights laws passed between 1866 and 1965, but, those laws were few and far between.