Touché, yes there's some truth to this. Many of the points in the post were reflections on people leaving my team as I have an order of magnitude more examples of that than me leaving a team. If you're implying there's some kind of zero-sum thing going on here though, I disagree: it can be good for both you and your boss.
> I wonder what their world view is…
I don't quite follow this paragraph, could you rephrase?
> Leaving the team at short notice is unethical?
Ah, no – this is in the "Don’t sabotage, it’s a dick move" section: it's sabotage which is unethical.