Their parents never taught them - don't take something that doesn't belong to you.
Real fucking simple.
I grew up fifty years ago learning from Rand that some people are looters.
She was very prescient - if you can't read the whole book, go to the chapter where the looters are meeting at the 20th Century Motor Company, and one who was redpilled:
They told us that this plan would achieve a noble ideal. Well, how were we to know otherwise? Hadn't we heard it all our lives from our parents and our school-teachers and our ministers, and in every newspaper we ever read and every movie and every public speech? Hadn't we always been told that this was righteous and just? Well, maybe there's some excuse for what we did at that meeting. Still, we voted for the plan and what we got, we had it coming to us. You know, ma'am, we are marked men, in a way, those of us who lived through the four years of that plan in the Twentieth Century factory. What is it that hell is supposed to be? Evil plain, naked, smirking evil, isn't it? Well, that's what we saw and helped to make and I think we're damned, every one of us, and maybe we'll never be forgiven…
Ayn Rand's view of how looters defined their needs, from Atlas Shrugged
Well, anyway, it was decided that nobody had the right to judge his own need or ability. We voted on it. Yes, ma'am, we voted on it in a public meeting twice a year. How else could it be done? Do you care to think what would happen at such a meeting? It took us just one meeting to discover that we had become beggars rotten, whining, sniveling beggars, all of us, because no man could claim his pay as his rightful earning, he had no rights and no earnings, his work didn't belong to him, it belonged to 'the family' and they owed him nothing in return, and the only claim he had on them was his 'need' so he had to beg in public for his relief from his needs, like any lousy moocher, listing all his troubles and miseries, down to his patched drawers and his wife's head colds, hoping that 'the family' would throw him the alms. He had to claim miseries, because it's miseries, not work, that had become the coin of the realm so it turned into a contest among six thousand panhandlers, each claiming that his need was worse than his brother's. How else could it be done? Do you care to guess what happened, what sort of men kept quiet, feeling shame, and what sort got away with the jackpot?