> The plumber generally exploits one or two employees. But otherwise your point stands.
It's hard to know where to start with things like this. How does the plumber exploit employees? Why are you assuming anyone exploits anyone by default?
Labour generates value. An employee generates value and the employer pays the employee only a fraction of the value generated, after paying off all expenses. That is called profit. Marx defines exploitation in the amoral sense, like exploiting natural resources.
Customers don’t get exploited in this way. They generally are also employees of some company that does exploit them, but that is a separate relationship.
It's hard to know where to start with things like this. How does the plumber exploit employees? Why are you assuming anyone exploits anyone by default?