Thank you for your interest in the topic of freedom. I do not really understand your question.
I do not even know how you define exploitation. If you add to the definition the "surplus value" thing. Then exploitation is pretty much everywhere, as the owner has to have some profit from his business. And if he does not have one, then he is not a good businessman and he will probably go bankrupt.
Capitalists (and libertarians) are not against humanity and helping other people. They just do not want the inefficient state to take part in that role.
Nobody's suggesting that workers should be paid 100% of their net contribution.
Do you think perhaps workers should be paid a minimum of 10% of their net contribution?