Allegedly, this world is more than 4 billion years old, and humans have existed for around 2 million of these. That means that for literally billions of years, no one believed in moral absolutes. There was no such thing as "good" or "evil" until a few hundred thousand years ago, when humans started making up religions.
For a moment, we're going to pretend all of the above is true. The world really is that old, humans really are that young, and all religions (except Evolution) really are just made up. That leads us to one of three conclusions:
1. Morality is, and always will be, entirely subjective.
2. Morality is objective, and suddenly jumped into existence at some arbitrary point in human evolution.
3. Objective morality itself gradually evolved, effectively meaning some races are objectively better than others (well, now we know why Darwin believed the caucasians would eliminate what he called the "savage races").
Obviously, the "best" option up there is option one. Morality is, and always will be, entirely subjective under Evolution. If we really are just animals, which themselves are effectively just worthless clumps of cells, there is no such thing as evil. To make this easier, let's just point out that a lot of atheists, such as Richard Dawkins, genuinely do take this option, believing that the universe has "no design, no purpose, no evil and no good, nothing but blind, pitiless indifference."
But if that's the case, morality is no more objective than ice cream flavors. You cannot make a subjective mistake. You can say "I don't like this thing", you cannot say "this is an evil thing". All of this means that, at the very least, Evolutionists lose every moral argument they have ever used against the Bible. They can't say the flood was evil, they can't say God gave evil commands, they can't say God should have given a specific command, they can't even say lying is wrong. So really, rather than trying to call the Bible evil or immoral, they should just say "I don't like the Bible". But again, that makes "good" and "evil" worth about as much as "good" and "bad" ice cream flavors. If you prefer strawberry over vanilla, good for you. In the Evolutionist worldview, if you prefer violent rape over voluntary marriage, no one can say you're objectively morally wrong for it. You can't make a subjective mistake, and so you can't be good or evil in Evolution.
By contrast, in the Christian worldview, morality is objective. This is because there is a standard against which to measure it. Specifically, God designed us for a very particular purpose. "Good" is when that purpose is fulfilled to a satisfactory standard, or when that standard is not held to and so adequate (by God's standard) correction is made. "Evil" is when that purpose is not fulfilled to a satisfactory standard, or is actively opposed. And we can have an understanding of how to do each based on the commands given by God, be they through Scripture (2 Timothy 3:16-17), or by the significantly more limited understanding of our conscience (Romans 2:11-15).
An example of this is marriage. When questioned on divorce in Matthew 19:1-10 and Mark 10:1-12, Jesus points back to Adam and Eve, asking "have you not read" before quoting Genesis 1:27 and 2:24, basically saying God intended marriage to be an unending one flesh union between one man and one woman. It is understandable, then, that God hates divorce (Malachi 2:16), and commands against adultery (Exodus 20:14), prescribes the death penalty for rape, which is considered murder (Deuteronomy 22:25–27) calls homosexuality shameful and unnatural (Romans 1:26–27), forbids cross dressing (Deuteronomy 22:5), curses those who commit bestiality (Deuteronomy 27:21), doesn't even hold you blameless if you so much as look at someone with lust (Matthew 5:28), and of course presents monogamy as the ideal system (1 Corinthians 7:2). All of this is based entirely on God's design for marriage as seen in Genesis with Adam and Eve. And so we can say "this is good" or "this is evil" based on how well it matches with God's design and commands.
Now here's the problem. None of us hold up to God's standards. Every single one of us, Christians included, rebel against God regularly. And so He has prescribed only one remedy: Death. But the good news is that He hasn't just said "you're guilty, off to Hell with you". In His mercy, He created and exploited a loophole. If a worthy sacrifice takes your place, facing the wrath of God on your behalf, you no longer have to. Enter Jesus, the Son of God. God in human flesh, Jesus was born of a virgin, lived a perfect life, and died on the cross, bearing our punishment for sin. But He didn't stay dead. He rose again, guaranteeing that anyone who confesses Him as Lord and believes in His resurrection will be forgiven for all their sins, receiving instead the free gift of eternal life.
If Evolution is true, that's just a made up story, and we are living in a world in which nothing we do really matters. But I think every one of us knows that morality does exist, and it's far more than just my opinion vs. yours. Not only that, but we have all done evil things. Things for which we will be held accountable. Now, suddenly it seems obvious why Evolution was made up, and why people are so desperate to cling to it. Because if Christ really is risen, if sin really is real, we love it, and we have to choose between either denying ourselves or denying Him.