Ayn Rand identified the root cause: Altruism. When your morality demands sacrifice above all else it does not matter how many times this suicidal empathy fails. Sacrifice itself is defined as the good, results are irrelevant to that kind of belief .
Hence the lyrics, "Tax the rich, feed the poor, till there are no rich no more."
You'd think they'd have sung "till there are no poor no more," but no.
With leftists, altruism does not mean they sacrifice, but that you sacrifice. Altruism is at the core of Christianity, but it is the Christian who is supposed to give up everything for the sake of Christ, which is why it is harder for a camel to go through the eye of a needle than a rich man to enter the Kingdom of God.
One of the errors of Pope Leo XIV calling for universal health care is that what he really means is that taxpayers should be forced to pay for healthcare for everyone. The Catholic church used to build hospitals and medical clinics for the poor, spending their own money in God's work, which is how it is supposed to be; now they browbeat everyone into forced sacrifice, which only leads to fraud on the receiving side and resentment on the forced-giving side.