What if you were as competent as your better paid colleague but were just in a situation that limited your bargaining power at the time of hiring? Say you just

What if you were as competent as your better paid colleague but were just in a situation that limited your bargaining power at the time of hiring? Say you just had a baby or you're suffering from a disease and depend on your employer's insurance? You can't afford to not have the job, while your better paid colleague could walk away. Every negotiation favors the person who can afford to walk away from the deal. In a salary negotiation, this puts healthy, young, and single people at an advantage. It penalizes people with disabilities, disease or dependants - the most vulnerable groups. That's where the demand for open and fair compensation comes from.