> why you think so?

Because human nature is inherently selfish. The great majority of people generally tend to do stuff that benefits them and their close ones. Capitalism recognizes that and realizes that the great majority of value created by self-interested people is captured by the society in form of innovation, creation of products and services, jobs and taxes.

Societies that reject this truth (communism) tend to starve since nobody does anything anymore and everybody tries to steal from the State.

> Slavery is extremely profitable

This is false at a society level. In the USA for example slavery was abolished when the industrialized North won the war thanks to its better industrial and economic performance. Turns out a society of self-interested free individuals is much more profitable and successful than reluctant slaves in chains. As soon as countries realized it - they abolished slavery.

> where do you see the line?

Some rules are essential for a rule-of-law society (like contract law, judiciary, police, externality taxation, etc), others are well intended but imply costs and time which adds up (see how housing is unaffordable due due to regulations making it impossible to build) and finally some are frivolous and should be avoided at all costs (EU's USBC charging ports come to mind).

> You genuinely feel that profit motive will allocate this better

Absolutely. Read up on how markets work and how they they are only mechanism we know for solving the pricing (valuation) and resource allocation problem.

> rationality and ethics?

The wallet always hits above. No starving person is ethical. During my life under communism I saw the worst human abuse imaginable all from people who in theory had no profit motive. Human nature is human nature.

> What profit is there to be gained from feeding the poor?

Are you kidding? Why do you think all those food companies exist if not for profit? In capitalism there is a glut of choice to the end that obesity is a big problem. In communism we kept looking hungry at empty shelves.

> I just don't see how profit could possibly align with actual human ethics.

This is getting too much to explain for me. I recommend reading up on free markets. Watch Milton Friedman's series, it's free on YouTube and it explains things extremely logical and much better than I ever could.

https://www.youtube.com/playlist?list=PL10CF0016FC94D2ED

> Where does that statement come from?

Who knows? They had to pretend some higher purpose to cover the fact that we were cold and staving. We knew how much better things were under capitalism so instead of denying it they went for heroics. No food but the state built ICBMs? It was "for world peace". No heating or A/C but with a space program? "For the betterment of all mankind". All kinds of pharaonic projects, monstruous brutalist monuments dedicated to our leaders were justified that way. We didn't believe them of course, but they just had to lie.

Watch some Cold War era movies or documentaries if you want to understand how it really was. I am sure you can find a bunch on YouTube. I can't recommend any, the memories are too painful for me.

> USSR was a state capitalist nation

So "war is peace, freedom is slavery" then. Communists always had this funny habit of trying to rename things, to pretend they were somethin else, trying to muddle the waters. Orwell saw right through them. Us that lived their horrors too. But I am not interested in discussing dialectics. The end result of all communist experiments was starvation, no matter how you want to call them.