Reading all this lends credence to my general thought that people are pretty good in isolation, perhaps mostly because they need to worry about their own survival. As soon as they get together in groups, a lot of bad shit can and does happen almost purely in the name of good intentions.
If anyone knows who Bo Burnham is, allow me to quote a part at the end of his song "Love Is." Love is... being the owner of a company that makes rape whistles. And even though you started the company with good intentions trying to reduce the rate of rape, now you don't want to reduce it all because if the rape rate declines you'll see an equal decline in whistle sales.
It's easy for a group of people to convince themselves that (using the example above) eliminating that one guy and taking his farm over there is a good thing, cause more people would benefit than would suffer cause we'd spread the wealth of that farm around, and that guy is a dick anyway. So yea, there's no good reason not to do it. Meanwhile, you've completely ignored the fact that maybe he's not so bad, you just let your greed get in the way of objectively evaluating him. And the reason you want his farm is because he's smart enough to figure out a way to get a better yield. So sure, kill him, but no one is left that understands how he got that higher yield, and now that you've killed one guy, it's not big leap to kill another, and another and another, again, all in the name of good intentions. That's authority for you.
To Gator's point though: just like socialism, it just takes one asshole to fuck it up. That system relies on everyone thinking the same way, holding their envy in check, holding their aggression or gluttony in check. We all would like to think that people will make the smart, altruistic decisions but they won't, not all of them anyway, not all the time. That's probably why the founders saw government as a necessary evil.