Um...... Hellew.....<quoted text>
None were killed for being Christians, based on your own source:
"In addition to Jews, the targeted groups included Poles (of whom 2.5 million gentile Poles were killed) and some other Slavic peoples; Soviets (particularly prisoners of war); Romanies (also known as Gypsies) and others who did not belong to the "Aryan race"; the mentally ill, the deaf, the physically disabled and mentally retarded; homosexual and transsexual people; political opponents such as social democrats and socialists; and religious dissidents, i.e. members of Jehovah's Witnesses."
Jehovah's Witnesses are Christian.