Atheists can go ahead and say they do not hate God but deep within, they really know He exists but they hate Him. They do acknowledge God exists but the problem they have is submission to His authority. As Psalm 14 writes about atheism, it also writes in verses 2-3 saying, "The LORD looked down from Heaven and upon the children of men to see if there were any that did understand and seek God. They have all gone aside, they are all together become filthy: there is none that doeth good, no not one." and Psalm 53:1 says, "The fool hath said in his heart, There is no God. Corrupt are they and have done abominable iniquity there is none that doeth good."
Sin is not just a fantasy word as it is the very act of rebellion against God and the consequences of sin never change. God is not unjust to demand separation from sin because of its ill-effects. There is nothing justifiable about murder, stealing, adultery, fraud or any violation of God's law all in the name of just trying to survive. Doing something against God's Law is in effect rebellion against God and an affront to His holy immutable nature. Matthew 1:21 says, "And she shall bring forth a Son and thou shalt call His name JESUS for He shall save His people from their sins." If there was no sin, there would be no need for a Savior but most people hate Him because they love sin.
The Atheist's Moral Problem Towards God's Holiness
Will God Spare Judgment From Those Who Don't Believe in Him?