Identifying as Christian and actually being one are completely separate things. Hitler pretended to be a Christian in public yet hated it in private. Your own article even says this:

Nazi ideology could not accept an autonomous establishment whose legitimacy did not spring from the government. It desired the subordination of the church to the state. Although the broader membership of the Nazi Party after 1933 came to include many Catholics and Protestants, aggressive anti-Church radicals like Joseph Goebbels, Alfred Rosenberg, Martin Bormann, and Heinrich Himmler saw the Kirchenkampf campaign against the Churches as a priority concern, and anti-Church and anticlerical sentiments were strong among grassroots party activists.

Hitler’s Propaganda Minister, Joseph Goebbels, saw an “insoluble opposition” between the Christian and Nazi world views. The Führer angered the churches by appointing Alfred Rosenberg as official Nazi ideologist in 1934. Heinrich Himmler saw the main task of his SS organization to be that of acting as the vanguard in overcoming Christianity and restoring a “Germanic” way of living. Hitler’s chosen deputy, Martin Bormann, advised Nazi officials in 1941 that “National Socialism and Christianity are irreconcilable.”