They assume there's a fixed amount of wealth to go around and if they give anything up they should immediately get something more valuable in return else they're losing out.

In reality, by making certain trades or investments new situations and opportunities can be created, making everyone better off.

In a zero-sum game you benefit only when somebody else loses and vice-versa.

Which means if you make a deal with someone and they benefit from it - you lost. In other words - you should only do deals that hurt others.

It's a truly vile view of world, but what's more important is - it's false and counterproductive. There's no place for international cooperation in zero-sum universe. There's just exploitation through military or non-military means.

In a zero-sum game world USA does not join WW1 nor WW2. Instead it waits for Europe to collapse and invade to establish "American Europe". Anything else is suboptimal.

NATO makes no sense in zero-sum game world. NATO clearly benefits smaller countries which means it hurts USA. NATO should be therefore dissolved and let's shake them small countries for protection money.

The funny thing is - in such a world USA loses and China wins.

If someone is winning, it must mean someone else is losing (hence the "deal" sums to zero)

There is no comprehension that an agreement might actually benefit both sides

This is presumably why you hear such things as "Canada is screwing us for 200 billion dollars a year" because we buy things from them

Edit: you can see it in this thread, too. As though helping poor people could have no benefit to the rich

I've seen it with people complaining about paying taxes for public transit, even though they only drive a car. Bonus points if they complain about traffic in the same rant without ever putting 2-and-2 together

By denying access to basic services like education and health care, brutalizing the poor and enforcing laws selectively (black kid with few grams of weed = dealer; white kid with 50g and a digital scale = user), the government makes sure that the only options available to poor black people are misery or crime. Prisons are overcrowded and become effective schools of crime. Once you're through the system, you have very little option besides continuing to practice crime to feed yourself.

An extremely regressive tax system and overly complicated bureaucracy, designed to extract bribes, all but guarantee that only the well connected can invest and thrive, and makes sure that there is very little social mobility. Free education is available at all levels, but public basic schools are atrocious and public colleges have competitive admission, meaning that those with access to private education growing up get a subsidized degree from the government.

Building codes are rarely enforced so slum dwellers need not be paid more than enough to eat.

It is all very well thought out. Brazil is not underdeveloped. Brazil is a slave society with extra steps.