This ignorance makes me so angry I can't put it into words.
You're such a loudmouth keyboard warrior on these issues, but do you actually work in a retail environment where this is applicable? Have you experienced being on the receiving end of theft? What about being the victim of armed robberies? I've been involved on the receiving end of both. And I can tell you that armed robberies are far more traumatic and horrific than regular theft.
Regular theft is a nuisance, an irritant. It certainly pisses you off. It is not a life or death issue though, it is actually by any sensible businessman known as a cost of business in retail that you work to minimise in the same way as you need to control your labour costs to survive. An armed robbery puts lives in danger and leaves people traumatised afterwards.
If a thief gets the same punishment as an armed robber, or even worse as you seem to suggest the same punishment as a murderer then what reason does a thief have to show restraint? Our laws punish thieves less than armed robbers who are punished less than murderers. If you punish them all the same then a thief may as well kill all witnesses and leave no survivors leading to
MORE people dying.
Any sensible individual or organisation tries to keep people calm in the event of a robbery to minimise risk to life, not cause FEAR to those involved.
EDIT: PS in my experience most theft from retail is committed by employees. In your twisted world if I catch an employee stealing then rather than dismiss them and call the cops should I beat my colleague to death instead?