Capitalism naturally sorts humans into two categories:
-those who have to sell their labor to survive
-those who own capital and extract profit from surplus value.

Every worker generates some amount of value (v) for a capitalist, which is by definition greater than the labor cost (l).  The quantity v-l is profit for the capitalist, who invests it into their own portfolio.  Portfolios compete with each other as little AIs that run this code:

-use human mind to calculate returns
-use human mind to sell/buy/invest to maximize profit

Bad portfolios die off or merge with bigger ones and the result is a wild, scrambling, alien orgy of profit seeking that pools more and more wealth into fewer and fewer hands.

I stole some of this from this essay if you're interested (it makes the case that capital is a real god that acts in the world): https://ianwrightsite.wordpress.com/2020/09/03/marx-on-capital-as-a-real-god-2/

Re: communism/socialism:
Ideally, democracy would use everyone's desires, weighted equally, to determine how to change the world.  Clearly, a system where all the buildings/factories/land/technology/intellectual property are owned by a shrinking number of people who make all of the decisions and a growing number of people who make none of the decisions isn't democratic.

Businesses are basically mini-dictatorships run by capitalists who always have the upper hand because the worker always has the threat of destitution hanging over them.  People can choose their private tyrannies to submit to, but there's no guarantee they won't lose everything with a little bad luck.

Socialists want:
-nationalized industries for human needs.  profit has no place in healthcare.  (socialists also want universal free housing, free education, food programs, etc.)
-democratic workplaces (for example: you could vote your boss out if your teammates wanted someone else)
-eventually abolishing private ownership of the means of production.  everything that capitalists used to use to extract surplus value is now democratically controlled by society
-communism is the ideal to strive for, basically using the power of people to construct systems that foster participation, monitor for power-feedback loops and stop them, and shape society to deliver for people according to their needs.

The main power workers have to wrestle power from capitalists is the strike.  Socialists see organized labor as a key building block in a successful movement.  As the connective tissue between workers gets strengthened, they can strike exponentially more effectively until general strikes are possible.  General strikes bring capital to its knees and force concessions that the workers can use to make life better for even more workers, who will join up, etc.

Socialists are frustrated with technocratic liberals like lesswrong folk, who generally think something like "if we just had the right smart people in the right places we can fix this" or "we just need to program a genie to magic the problems away".  But the truth is capitalism itself is already a superintelligent misaligned AI (or, more accurately, a bunch of AIs) and we can't get ourselves out of the problems it causes without directly opposing it.

Even the technocratic world I used to imagine -- a bunch of super smart policy wonks work out details in back rooms and give us good outcomes -- is completely undemocratic and would fail for the sheer reason it's not representative.  AI projects will fail the same way.  Experts don't have the same experiences or problems as the people they're supposed to represent and can't possibly counteract the biases that introduces.  Participation is the only way to determine CEV.

The easiest steelman I can think of (as distinct from “the most convincing steelman”, “the strongest steelman”, etc.) is just to observe that the Soviet Union—the paradigmatic communist country—was, while certainly worse than capitalist countries in some ways, also better than capitalist countries in some other ways.

Note: this is not a claim that the USSR was better on net, or that it was good (whatever such an absolute claim might mean), or that living in it was preferable to living in a capitalist country, etc., etc. Only that it wasn’t strictly worse; that on some dimensions, it was superior.

This suggests (though does not prove!) that there’s something of value in communism, that it’s not literally worse in all respects, strictly dominated by capitalism, and discardable without any loss whatsoever.

This is a very weak claim! And it’s also not clear what to do with this claim, even if we believe it to be true. But it does present a clear obstacle to simply dismissing communism and calling it a day.