Hell is never a fun topic to discuss. And of course, it shouldn't be, because it's not a fun place to go either. Being such a difficult topic, unbelievers like bringing it up more than believers do, because they can use it to paint God as evil. How could a good God send a human to such a terrible place?
The first thing to note is that Hell isn't just a natural consequence of sin, but also a just consequence. In fact, it is so just that it is different for everyone who goes there. The dead are not all lumped into one equally painful eternity just because they didn't believe, but rather, they are punished according to everything they did during their lives (Revelation 20:12-13). A "good" person (good being in air quotes because we all sin) will suffer less than a particularly evil person. What's more is that knowledge is taken into account as well. If you sin but don't know, you will receive a lesser punishment, and may even be excused of that particular sin entirely (Luke 12:47-48; Romans 2:12-16). Refusal to accept the Gospel also results in a less tolerable punishment than those who never got a chance to receive it, particularly if they would have repented if they had received it (Matthew 10:15; 11:22-24; Mark 6:11; Luke 10:10-14).
All of this tells us one thing: Whether Hell is a literal lake of fire (which some dispute) or simply a place that can be adequately described as a place of fire, it is a place in which no one will suffer any more than they deserve. But they won't suffer any less, either.
Which brings me on to a more pressing matter. Hell isn't a nice place, and unbelievers clearly recognise that, and so why are unbelievers so insistent upon going there? See, the thing about reality is that a fact doesn't have to be nice to be true. God is a real God, Hell is a real place, and real sinners must go there if they face God on the real judgement day without having placed their faith in the Lord Jesus Christ. Unbelievers do not like this fact, but as Ben Shapiro is famous for saying, "facts don't care about your feelings".
Furthermore, God Himself does not like the existence of Hell. His word is replete with verses that tell us He takes no pleasure in the death of the wicked (Ezekiel 18:32), preferring that the wicked repent (Ezekiel 33:11), that He doesn't want anyone to perish (2 Peter 3:9), and that He wants all men to be saved and come to the knowledge of the truth (1 Timothy 2:4). Hell was not even designed for mankind, but for the devil and his angels (Matthew 25:41). If we go there, we go there simply because we have sinned as he did. We can even be grateful for this: God did not make the same effort for angels as He made for us (2 Peter 2:4)! A sinning angel cannot be redeemed. Yet we can.
And so the logical conclusion is to not go to Hell. If you know that smoking causes cancer, it's not logical to say "it's not nice that cancer kills people, therefore cancer does not exist". The logical response to the fact that smoking causes cancer is don't smoke. So also is it not logical to say "it's not kind of God to send me to Hell because I sin, therefore God cannot exist." The logical thing is to go to Him to have your sins forgiven.
Just as cancer is a natural result of smoking, so also is Hell a natural consequence of sin. It isn't that your body is bad. Your body is good. Cigarettes, however, are not good for it. They damage it. In the same way, sin is bad for God, not in the sense that it somehow harms Him against His will (after all, He is God), but in the sense that it offends His perfect nature, and violates the purpose for which He designed you. Habakkuk 1:13 tells us that His eyes are so pure, He can't even look at sin. Thus, rather than being unkind for sending sinners to Hell, God is actually extremely merciful by giving them the chance to avoid Hell.
YOU'RE. STILL. HERE.
If you're still alive, you have the chance to repent of your sin. That's more than you deserve. You have committed the crime, and God is under no obligation to rescue you from serving the time. And yet He did. Jesus lived a perfect human life on your behalf, and died a sinner's death. Not just a sinner's death, but the very death that the Old Testament says is synonymous with being cursed by God (Deuteronomy 21:22-23; Galatians 3:13). He did that on your behalf, so that your sins may be forgiven. And so what's your excuse? "I don't like what God would do to me if I don't receive His forgiveness"? Ok, so receive His forgiveness! "I don't like what God will do to people who don't receive the Gospel"? Ok, so get out there and give them the Gospel. If you really hate the Doctrine of Hell as much as you say you do, get out there and make sure as few people go there as possible. Don't use the fact that God punishes sin as an excuse to remain in your sins and receive that punishment. Use the fact that God pours out His grace on those who turn to Him in faith as an excuse to reject your sin. I will never understand how atheists can spend so long objecting to the existence of Hell, yet follow it up with "therefore, I insist on going there, and taking as many people as I can down with me!"