Under Executive Order 9981, President Truman began the process for desegregating the United States Military in 1948. But the story begins before this, the push for military desegregation is part of the Double V Campaign. Victory abroad against Fascism, and Victory at home against Racism. The Civil Rights Leader A. Philip Randolph brought the idea of desegregation before President Franklin D. Roosevelt and again in 1947 to President Truman. The build-up to desegregation was a many year, very intensive affair. In addition to this, President Truman was more cognizant of African-American rights and struggles in the country politically, including the desire to desegregate the military.

Going back to his personal beliefs, and quoting the passage you presented: "Former President Harry Truman said yesterday he did not believe white persons should marry Negroes. He said that racial intermarriage ran counter to teachings of the Bible." It is no surprise that Truman would be willing to desegregate the military and increase the rights of African-Americans in the United States but still be opposed to interracial marriage and miscegenation. There were plenty of racial liberals at the time who would be pro-civil rights but against interracial marriage, it was just a part of the multifaceted image of the Civil Rights Movement. Much in the same way that Abolitionists would be anti-slavery but still extremely racist.