Hell exists because God takes rejection of his person very seriously, and that his justice will not tolerate it. Period.
Indians who lived in New France before Jacques Cartier ever came, some of them, I’m sure, must be in hell. How exactly, from your peculiar perspective, did they choose hell, of whose existence they were not even aware?
God came up with this “my way or the highway” deal, with this binary system where dissenters are punished by God himself way more harshly than Kim Jong-un’s uncle, breaking news God could have come up with a better system of eternal bliss or eternal torture. Annihilation sounds appealing, I’m sure a god less obsessed with revenge and avenging his offended self could have come up with something else. There is a difference between not allowing your enemies into your own home and burning them alive, putting out the fire before it kills them, then burying them alive and giving them air seconds before they suffocate. Rinse and repeat. Which is what hell is.
“God doesn’t want us to be slaves”. The damned sure do look like hopeless slaves to me. Wouldn’t it be better to be a temporal slave, unable to not love God and follow his will, than to be an eternal miserable slave? Surely, you don’t mean the things you say. You’re forced to follow the party line and rehash the lines they had you memorize, right?
Hell exists, not because it could not have been avoided, but because to God his justice is paramount. He will choose the satisfaction of his justice over the eternal fate of millions or billions any day. His justice is the sole reason there is a hell. Annihilation would deprive God’s justice of its precious satisfaction. In the absolute sense, God only loves those who love him.