In many countries, employment is “at will”.
This means that we can get a job without having to sign a multi-year contract and we can quit anytime we like if a better opportunity presents itself.
It also means that an employer can let us go at any time for convenience. If the economy is bad, they can let us go. If they don’t like the types of movies we watch on the weekend, they can also let us go.
There is more room for abuse in such “unregulated markets”, and most of the employment abuses comes from employers (employees don’t kill their income just to spite their employers). This is why corporate values are important. Values like trust, respect and integrity can prevent jerks from firing employees for no good reason. Where there is no rule, values fill the gap.
Leaders should meet regularly with HR to review recent terminations, with a goal to verify that they were both legal and ethical.