The idea of God's rules are "cruel" is a result of sinful man's desire to just seek for pleasure even at the cost of breaking God's holy standard. Let us just think of the "cruel" Ten Commandments which is not cruel but just. I thought about how the atheist looks at God's Law and how they tend to just appeal to it whenever it is convenient. They want to steal, they want to murder, they want to do this and that but wait until they have become the victim. I remembered how stupid it is to argue that there are no absolutes that they can lie, steal, cheat and do whatever they want. But wait until they are victims of such acts then they start crying foul and playing the victim that God is "unjust". So who was really unjust?
A good illustration of God's commands to why they exist is like a guardrail. Beyond the guardrail is death and Hell. People hate God's Law and they want to do what they want. This makes them even more obstinate to the Gospel of salvation. What is so stupid is that many people who live so wantonly in sin and loving their sinfulness think they are righteous people. When God demanded severe punishments for sin it is because sin brings in severe consequences. I would not want to live in a place with loose law enforcement because it is not safe. I may not be able to steal, lie and cheat and get away with it but because I cannot get away with sin, I can be certain that if sin hits me then I have every right to complain against offenders. But when you are in a place where sin is permitted then you have lost your right to complain against offenders when they sin against you.