It is correct that the business expects that your time and energy is worth more to them than it is to you. Profit.

But then literally every trade between two people—trading four sheep for one cow, say—is exploitation in both directions. I expect to benefit more from the product I receive than I can profit from what I give away. I have plenty of milk but need some wool for clothes. But to improve my own situation is somehow to abuse the other person!?

You’ve seemingly declared every form of economic transaction immoral.