> “Exploitation” has (at least) two meanings: 1. treating someone unfairly for one’s own benefit 2. make use of & benefit from some resource

When you're referring to two people, then exploited always refers to definition 1.

Have you ever heard anyone say "I exploited my employee" in a context where they're referring to definition 2?

If you're talking about mineral deposits or something, then sure... you can apply definition 2. "The company exploited the ore's rich iron deposits".