If you see a leftist’s motivations as greed and feeling good, you can explain a lot of their preferences and decision making. They direct their anger toward imagined boogeymen—people who disagree with their self-gratification ranging from their parents to conservatives. They gin up evil images of their opponents in their minds to provide a foil to themselves and make their opponents as evil as possible so their own transgressions are never as bad as their opponents’. If you have done what many leftists have done, such as their treatment of children, your imagined opponents have to be really, really evil to make yourself feel like a better person.
And this is why liberalism is such an easy sell. The “generosity” of wanting to control other people’s money and actions “for the betterment of all” grants them a feeling of (false) virtue.
Tell a fool that he can be greedy and vain, and disguise it as probity, and you have a new liberal convert.