Some Christians, however, truly are "satanic". Hitler, for example, had spiritual beliefs and remained a member of the Catholic Church until his suicide. And the abominable sex abuse by clergy is so widespread that is has become synonymous with religion. It is "satanic". Of course there are atheists who have also behaved "satanically". The point is, however, that neither traditional spiritual beliefs, nor a lack thereof, necessarily entail "satanic" behavior. Like many people who hold traditional spiritual beliefs, most atheists are caring, law-abiding members of their communities. Indeed, some studies suggest that they are less pone to criminality than people who hold tradition religious and spiritual beliefs.
Attempts to link atheism with satanism just don't stand up to even superficial scrutiny.