Like this is what I don't get - how is it in any way fine to fire probationary employees ? Like isn't like totally wrong, rude and overall totally treating tho

Like this is what I don't get - how is it in any way fine to fire probationary employees ? Like isn't like totally wrong, rude and overall totally treating those people like garbage without any fault at their side ? What justifies such a totally insane behavior ? How do you expect anyone willing to work four you in the future if you treat people like this...