Defintion of Atheism according to atheist- To Not Believe or lack belief in God or gods

A look through the eyes of a Christian who knows God.
All people who deny Jesus Christ as God are atheist that is according to Christianity and God himself.
That includes muslims, buddhist, nazis, evolutionist, pagans etc.
Had they believed in God they would not have rejected Jesus thus they became their futile selves atheist. Beings without pure knowledge.