That response article (whether intentional or not, I can't say) horribly misunderstands and misrepresents the POSIWID axiom.

It's not about the outcomes of something taken in isolation, it's about the actions taken in order to achieve it, and when those actions continually run counter to achieving the stated goal.

So the response article examples are missing half the context needed to make it's claim:

* The hospital only curing 2/3 of cancer patients being simply a failure to achieve it's true mission of 3/3 cures would rely on knowing it is taking action in earnest to actually cure all patients.

While we can assume that for an obvious hypothetical, if for instance a whistleblower leaked evidence showing that 1/3 patients were being intentionally withheld care, the hospital responded it was an accident, but then evidence came out proving they still did this, then POSIWID would apply.

In a real-world, non-hypothetical example:

ICE keeps deporting American citizens. Every time this gets reported on, they insist it's a mistake. They keep doing it.

Insisting that adverse behavior is an accident/mistake/incidental, but then continuing to do the bad thing yourself, is the purpose of the axiom.