I see this fallacy all the time.

Can a 40 year old man have sex with a 12 year old girl if she agrees? What if she's 18? The first is illegal and wrong. The second is legal but most people will tell you it's at least gross. Why? Because of the power differential.

Starting a company takes investment (obviously money but also time spent on administrative tasks, hiring, marketing, etc.). Rich people can just buy companies and get passive income.

Salary negotiations are also unequal - one side has much more information and almost always more time and monetary reserves.[1]

I am tired so i'll cut it short - there's inherent power imbalance in the employer-employee[2] relationship which makes the outcome inherently and unavoidably exploitative.

[0]: They'll often use the word illegal because they have been taught to follow rules but have not been taught about differentiating legality and morality.

[1]: Why do you think you come to the company to the interview instead of them asking to meet you at a restaurant like normal business deals might be discussed? It's so ingrained this is normal that what I said sounds absurd.

[2]: Have you ever thought what those words actually mean? Employees are literally being used, it's right in the name.