If only "some" people (or atheists - that point isn't very clear) do things such as "slave trade women and children every day of the week", that implies that the majority does not. Thus, if we're going to play the 'poisoning the well' game, we can tar every xtian with the child rapist brush, with exactly as much justification.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'