You can't compare selling goods to employing people in that way. Consider the fact that there are humans on both sides. Businesses can use their power to abuse

You can't compare selling goods to employing people in that way. Consider the fact that there are humans on both sides. Businesses can use their power to abuse employees in a way that can't be done to goods. If you are the main source of income for a person, you have massive influence over them. Government creates laws to balance the power. There are countless cases of abuse by employers including physical and sexual. Very different from selling goods or having a gym membership.