"If God exists, then why..." This sentence can be followed up by a number of arguments. Why does He allow evil? Why doesn't He show Himself? These arguments are understandable. These are valid questions that even believers may struggle with.
But then you come to other silly statements, like "why does Christian music suck?" (No really, someone made that argument). I don't subscribe to the idea that there is no such thing as an atheist, but I do quite firmly believe atheism is deliberate. This is evident by the shields they put up in order to maintain their beliefs.
I've been an apologist for more than a decade now. I've debated large numbers of atheists, and although I have experienced some intelligent ones, the overwhelming majority of atheists put up the strangest barriers to their own faith. For example, one atheist responded to an argument I had made against Evolution by asking my opinion on pancreas cancer, and saying that because I had no opinion, my opinion on Evolution is wrong.
And so I contend that atheism is deliberate. Again, I would like to reiterate that I do believe atheism can be genuine. Biblical evidence does seem to suggest that it is possible, though foolish, to believe in your heart "there is no God", and that those who persistently reject God are even given to their own delusions. However, although I believe that some, maybe even most atheists genuinely believe there is no God, the evidence suggests they are deliberately deluded. It is not a conclusion they have reached naturally, but out of rebellion against Him.
If you are an atheist, I'd like to challenge you to examine your general strategy when discussing God. Pick your top arguments and ask whether they are logical. Remember, in order for an argument to be valid, it must have correct premises, which logically lead to the conclusion that God does not exist.
A common example of an invalid argument is the so-called "politician's syllogism":
Premise 1: Cats have 4 legs.
Premise 2: My dog has 4 legs.
Conclusion: My dog is a cat.
In this example, premise 1 is generally true. Of course, not all cats have 4 legs, but cats do typically have 4 legs. Similarly, dogs typically have 4 legs, and so if you have one, it probably has 4 legs. I have both cats and a dog, and their limbs are anatomically intact. But the conclusion "my dog is a cat" does not logically follow from the two premises, however correct they may be. Let us look at the aforementioned musical argument through this lens. Reduced to a syllogism, the argument would be:
Premise 1: If God exists, Christians should make good music.
Premise 2: They don't.
Conclusion: God does not exist.
This argument is illogical. Both premises are highly flawed, and the conclusion does not logically follow from either of them. Premise 1 is flawed because nothing in Christianity says God must grant His followers excellent musical abilities. In fact, it clearly says God gives all people various gifts; we all have our strengths and weaknesses. Faith merely dictates whether or not we use those to glorify God. Premise 2 is flawed because aside from "good music" being entirely due to subjective tastes, some Christians have made history with their God-honoring music. Because both premises are flawed, and because the conclusion does not logically follow them anyway, the argument is invalid.
Now let us apply this to the first good question: If God exists, why does He allow evil? This is actually a half decent argument, if massively outdated. Reducing it to a syllogism, we would come out with something like the following:
Premise 1: If God exists, evil should not.
Premise 2: Evil exists.
Conclusion: Therefore, God does not exist.
This is at least a logical argument. It makes sense that if an omnipotent, omniscient, and omnibenevolent being exists, evil should not. Similarly, it's easy to see that evil does exist. And if we can demonstrate that both premises are flawless, the conclusion is the only logical conclusion. However, there are a few flaws even here.
First, premise 1 can be refuted by its own syllogism:
Premise 1: We are evil.
Premise 2: God loves us.
Conclusion: Therefore, in order to destroy evil, God must destroy those whom He loves.
The best passage to demonstrate this is 2 Peter 3:1-9. In it, we are told that God does not want anyone to go to Hell, and so He is waiting to judge the earth. A time will come when He will destroy all evil, but if God waits, He can save more people. If you're an atheist, think of it this way: If God destroys all evil right now, you will die. If God waits, you might be saved. Even if you, personally, won't be, others might. And so it just makes sense that God is waiting for the right time to destroy evil.
The second premise of the problem of evil, namely that evil exists, ironically borrows from the Theistic worldview. If there is no God, there cannot be any such thing as evil, because there is no moral law giver, and thus no moral law to violate. Basically, if there is no God, there is no evil. Or, to put it as Richard Dawkins did, if there is no God, there is "nothing but blind, pitiless indifference". Therefore, we can construct the following syllogism:
Premise 1: Without God, evil cannot exist.
Premise 2: Evil exists.
Conclusion: God exists.
And so we see that atheists can't win either way. Their best arguments fail, their worst arguments suck. The question that must therefore be asked is why atheists remain atheists? As previously mentioned, it is a heart issue. Atheism is deliberate. But just as it is deliberate to remain in, it can be deliberate to leave. All atheists have both the right and the ability to repent and be saved.