You misunderstand, I guess because I kept my post brief. This person was a software engineer working for a non-kibbutz company, so the non-kibbutz company was paying that person's salary to a kibbutz bank account rather than to the person. The salary was about $30,000/year for an end-of-career senior developer, who was easily worth triple that or more. From her perspective, she didn't see a point in trying to move jobs or ask for market-rate, because either way, whatever salary she earned went straight to the kibbutz. The kibbutz didn't complain about the exploitation salary because it was "enough" and the non-engineers running the kibbutz didn't know what people are supposed to be paid.

So everybody loses. The kibbutz loses because it gets way less hard cash than it would otherwise be able to get. She lost, leave the economics out of it for the sake of argument, because the reality of exploitation is that you suffer in your work relationships as a result.

A kibbutz doesn't give you job security. If you are supposed to be earning from outside the kibbutz, and stop working, then you face social ostracism and shame within the insular community. That's not security.