Is it time to start calling out bad cyclists?

I'm not sure the word 'immutable' really adds to the point)

It was your question in the first place.

some people steal bicycles.
Those people are bike thieves.

They are the external agent. Locking or not locking does not change their existence, nor the threat they pose. They exist. That cannot be changed within the context of locking the bike up or not this one time.

Is there really a difference between the two? Isn't the distinction between assuming responsibility 'in the face of an external agent' the same as assuming responsibility 'for the actions external agents'?

One is assuming responsibility for oneself. Not for the bike thief.

The other is assuming responsibility for someone else.

Now - If you don't stop, I'm going to tear my kitten's throat out. This will be your fault. And I mean full stop. From the forum. From the internet. Your fault. Dead kitten.

This new forum quoting function is utterly dire.