According to an old Christian sparring-partner of mine, atheists can't argue in good faith because we don't have any faith! That one made me chuckle. It also allowed me to point out that we can't argue in bad faith, either.
For me it's all about putting the cart before the horse. Because if God exists, and is perfect, why did He then create imperfect beings in order to punish them for their imperfections? I could understand if the claim was all the trials God places before Humanity were intended to improve us and make us perfect. But apparently they are just to test the faith of believers. Interesting hobby for God, no doubt, but hardly conducive to progress.
If, on the other hand, we put the horse in front, and argue that as a Human construct, God will necessarily have Human flaws, then everything makes at least as much sense as it can in a Universe without meaning apart from that which we create. But that's a pill too bitter for believers to swallow.