Some atheists, understandably, might have some difficulty trusting
people who determine their actions through their assumptions about the
whims of their imaginary friends in the sky.   But apparently the
tosser has difficulty trusting people who don't.  Might be about
psychological patterns of submission to authority and/or something like
the atheist would rather deal with people who have demonstrated
capacity for reason and love, the tosser would rather deal with people
who have demonstrated capacity for obedience and faith.

Or maybe it's just that it might be easier (I have no data) to convert
someone from one faith to another* (typically the tosser's), than from
no faith to a faith - i.e. the viral meme complex of the tosser wants a
hospitable environment, and one with potential hosts that are
susceptible to similar viral meme complexes is preferred to one without
such potential hosts where propagation is therefore impossible, even if
it means the meme complex has to compete with others for control of
hosts... :-)