I think Crude nails it here:
Here’s something I’ve seen happen over and over: a theist makes an argument, or a criticism of atheist or popular secular reasoning. It happens to be strong. Atheists realize – well, THIS conversation can’t be won. So they immediately try to change the topic. The best bet: criticizing God, or the religion of the people involved in the discussion, especially if it has nothing to do with the topic at hand. And it’s the best bet because inevitably someone decides that they have to defend each and every slight against Christ or God or Catholicism or Protestantism or what have you, and before you know it the topic is no longer the weakness of a given atheist or secular claim, but Christianity or (worse) Christian in-fighting.
In a word, they get suckered. They go from focusing on a failing of an atheist or secular claim to being on defense. And the worst part is, they think they’re helping their cause. After all, look at them – they’re defending Christianity or Catholicism or whatnot!
Except, sometimes the appropriate thing to say is ‘Your criticisms of God are irrelevant here. We’re talking about another subject, and it stands or falls regardless of the truth of God’s existence, or your views of His moral character.’