Well, one could ask: why did souls incarnate an masse into the Roman Empire, which was basically such a brutal and sadistic regime? Or the same about the Soviet Union, especially under Stalin, as provoced abortion was the rule, but there were still live births - by women who manged to hide their pregnancy and insisted on being mothers, despite the hard conditions and the sentences they would face for giving live births. Or even the Republic of China today; an inhuman, totally culture hating regime. Why do souls incarnate into what the rest of us concider being societies of hell on earth?
I dont know for sure, but I would suggest its to be able to live a human life under inhuman conditions. To be able to work out change under horrific political conditions. To bring the humanity in, where humanity does not exist anymore. To bring God in, where God has been driven away by hypocrites, murderers, perverts and the sadists in powerful positions - like Jesus Christ did, as he incarnated in Betlehem, which was a part of judaism, but also a province of the terrible Roman Empire.
And as you all know; Jesus, won over the regime. Because neither the jewish kings, nor the pharisees nor the Romans could bring him down. Even not by torturing and killing him.
So I think it basically shows the purpos of incarnation into the hellish conditions. To bring God in. And that makes the whole difference between living in hell and living on earth.
The possibility of life on earth requires love, and it works out love. If there exist no love in a hellish society, there will be no incarnation of souls either. But the love of God lives among the human being, and God wants to bring his love into the hellish conditions, to bring change and peace and holiness to all of humanity. And this is the reason for life on earth; to bring in Gods love and light up the whole universe by it.