Why is severity desirable? Or if it's not desirable, so what?

Severity is desirable iff it's justified. I wouldn't ever sign off on a policy that says "you'll be fired for a single mistake" (that would be a severity of punishment out of proportion to the risk/underperformance).

But a policy that never provided for the possibility of termination (insufficient maximum severity) is also not desirable.

> Severity is desirable iff it's justified.

It's necessary if it's (necessary & efficient & justified); it's never desirable IMHO.

Doing severe things because they are justified is just acting out on a desire or drive - internal anger - but now we can 'justify' the target and feel ok about it. Lynch mobs think they are justified.

Designing severe things to be included as part of a process is a desirable property of that system if the severe thing is sometimes required.

No one is designing a formal system that includes lunch mobs. But a formal system of repercussions for employee behavior that does not include firing is an incomplete system.

It’s not that firing itself is ever desirable, but rather that its inclusion in a disciplinary progression is desirable.