Adam is losing the use of his basement for the month. He could otherwise have stored his things down there, or had a sleepover party down there, or fermented wine down there, or set up a Bitcoin mining cluster. The fact that he can't do these things for a month represents a cost to him that he recuperates in his rent.
It's unfair that Bob should pay Adam for work that Adam isn't doing. Adam can enjoy the benefits of doing those things if and when he does them.If Adam breaks Bob's leg, and this causes Bob to be out of work for a month, would it be fair or unfair for Adam to pay Bob his month's wages as compensation for the loss Adam caused Bob to take?
Not if Bob wanted Adam to break his leg.
I think this is a really hard area beacuse free market and anti-exploitation arguments tend to argue right past each other. I think both tend to have some interesting, and even valid points. However, I tend to feel like anti-exploitation is making a statement about how we as individuals should want to act towards eachother, whereas free market arguments seem to avoid any talk of motivation, and focus solely on the transaction.
At Yale some professors (or at least a math one) put lectures on youtube, I watched a few on "game theory" recently. So I am no expert, but I feel qualified to now talk out my ass like I think I am one. This all reminds me of the Nash Equilibrium. The set of moves where everyone has played his best possible move, in relation to everyone else's move. Nash himself postulated that you would have a very stable society without wars if everyone had a paranoid fear of everyone else and acted in complete self-interest. Nash was also a paranoid schizophrenic, so this concept may have come naturally to him
The interesting thing is, that depending on the definition of the game, there can be multiple such equilibriums, and they are not all equal, that is to say, some raise the overall score more.
So to half ass connect this. If Adam rents Bob his basement. The free market argument is, Adam could have made more money setting up a workshop down their with Carol, or brewing beer with Dave. So if Adam feels he should charge more for the basement to justify not using it for that, then thats what he does, and that price is of course fair by definition because, its his to sell.
The exploitation argument is that if Adam is going to rent to Bob, he should do it because he wants to do it, because he values giving Bob shelter. Of course, he incurs risks and costs, and needs to ask that Bob "pull his weight" and make sure Adam isn't just incurring more cost for slogging his dead weight along.
The thing is.... if Adam has other uses for it, and deicdes that he doesn't value (or can't afford to value) housing Bob above other things he can use the space for, then he should do those other things right? So... both arguments seem to end up at the same place.... but they are not even trying to talk about the same aspects of the transaction.