Not every aspect of economics has to be wrong in order for your preferred economic theory to be correct.

It’s hilarious how socialists/communists/idiots will disagree with anything and everything about economics, as if they “win” by default if economics is wrong. Yet they fail to realize their own theories would fall apart too if they deny even the most basic building blocks. Marx’s theories of exchange are also based on the principle that people trade on this basis of mutual benefit. His theories of exploitation don’t rely on workers being so stupid that they don’t realize they’re trading their labor for too little; his theories rely on the idea that they simply can’t get as much as they’re worth because of the capitalists’ power.

I’ve had self-described Marxists tell me that capitalists always collude and competition never drives down profit rates. The guy didn’t realize Marx’s whole theory of economic crisis is based on the idea that capitalists drive drown profits through competition.