There are three basic ways in which humans interact:
1) slavery – the interaction wherein I tell you that “unless you do something good for me, I will do something bad to you.”
2) economic cooperation (profit) – the interaction wherein I tell you that “if you do something good for me, I will do something good for you.”
3) generosity (gift-giving) – the interaction wherein I tell you that “I will do something good for you, and do not expect you to do something good for me.”
These are in what we have historically perceived to be increasing ethical order. Of course, rarely are our interactions purely one of these – nor are they perceived to be. And the interactions are oftentimes very complex. And this can get us into trouble, since 1) is always unethical. But what is happening if I am an employer, and I hire someone? Certainly this is 2), but if I hold the threat of firing the person if they do not do their job properly over them, it is perceived that the interaction is also 1). But is it? Just because I withdraw 2), it does not mean that the interaction I am having with the person is in fact 1). The worst I can do is fire the person from the job that it was mine to give him. And when he ceases to do something good for me (do a good job), then I am under no obligation to continue doing something good for him (keep him employed) under interaction 2). If I were to keep him on, it would be due to 3), which is not the purpose of a place of employment. The purpose of a place of employment is to make everyone working there profit – to make everyone there better off than they were before they entered into interaction 2).
Any time a government interferes with either interaction 2) or 3), it is interacting with people with interaction 1), and thus is acting unjustly. Only when government works to prevent others – including itself, from engaging in interaction 1) does government act justly.