Evolutionists, I'm going to attempt to explain the moral argument to you.
We both agree that there was a time in earth's history when there was no human life. In my view, that was a very short time, a mere 5 days. God then created human beings, giving Him the absolute right to give them whatever commands He saw fit, and punish them however He sees fit when they disobey. Thus, in Christianity, it is entirely logical to say "this is right because God says it is right", "this is wrong because God says it is wrong", or "this is a grey area because God's word doesn't necessarily give us a concrete answer". It also makes sense to say anything that is not explicitly forbidden is implicitly allowed (2 Timothy 3:16-17).
For you, however, life has been progressing for millions of years. First, a single celled organism just magically popped into existence. No idea how, it just did. This eventually evolved into a bunch of plants and animals, none of which had any kind of moral compass. In fact, a lot of the things we would consider immoral for a human to do to another human, they did to each other, and that is the very process that created us.
During the time human beings didn't exist, there can't have been any moral laws regarding how to treat them. You can't care for what doesn't exist. Thus, Evolutionists are forced to explain exactly how morality started to apply to human beings. But there's no mechanism by which objective moral values could possibly come into existence without a god of some form.
Basically, in Evolution, morality is a social construct. There is no "right" and "wrong", there is only "liked" and "disliked", and ultimately, the one who is "right" is the one with the biggest gun. It's not about "it is right to do this", it's more "I'm strong enough to make you do this."
And it gets far worse. In Evolution, humanity isn't really the highest level. Sure, we got this far, but another species could get much further. What if, one day, a species develops to the point where they are able to subjugate us as we subjugate the rest of the world? Say if one race becomes so developed, they are as distant from us as we are from the apes, and so they decide to treat us as we treat the apes. Could we object? Not really. They're stronger, they're smarter, they win, bad luck Adam. (It's worth noting, Evolutionists such as the notably caucasian Charles Darwin believed caucasians were that race, and all other races were savages who would soon become extinct).
Thus, if Evolution is true, morality cannot really exist. This, first of all, refutes every possible attempt to accuse God of immorality. Morality requires God to exist, and thus it is impossible for God to be immoral. At best, God can be disliked by sinners over whom He has absolute authority. Second of all, the fact that we all recognise that morality does exist is a good indication that the Bible is true.
Romans 2:12-16 tells us that God has programmed the human race with moral instincts. We understand the basics of morality by nature, not because some monkey man, who lived millions of years ago, realised bashing his friend's head in with a rock might mean there will be less monkey men in the future, but because there are objective moral laws that we are obligated to follow, and that we ultimately will be held accountable for our failure to follow. Every single one of us has failed, and there is no excuse.
But God is more merciful than to just give us moral instincts and punish us for disobeying them. Rather, God Himself, in the person of Jesus Christ, came to the earth to be born of a virgin, live a perfect life as a human being, and get crucified. He died a sinner's death despite having no sin of His own. He then rose from the grave. Because of all of this, the rift between God and man is fully repaired. God no longer has to judge us for our evil, because He instead judged Jesus. Now, all it takes is faith in that, and when we inevitably die, we can inherit eternal life in His Kingdom. Now, I don't know about you, but that doesn't seem like the kind of offer worth turning up for silly stories about fish deciding to take a leisurely stroll across the beach.