Did I misread his post? It read to me like he is saying the complete opposite: That the example in the article sounds more threatening than just being genuine.
That was just a tongue and cheek example to make my point clear ie. direct communication in favor of passive aggressiveness. I'm not advocating for threads, I think you found a straw man.
The original post was not intended at teaching the reader how to make a passive aggressive conversation effectively. It was actually about making honest and direct communication without biases and preconceptions. The whole post, to me, was about how to not jump into conclusions about the other person.
This style of communication isn't angled at 'normalizing' anything. It's meant to give you a framework to identify what the real problem is, to communicate it clearly and efficiently, and to work with the other person to move past the problem. If you don't say exactly what you're trying to say, and someone later 'found out what you "really meant to tell them' - you 100% did it wrong.
It's not a way to get out of having a difficult conversation. It's a framework to help you remove your personal beliefs, remove values judgments, and instead rely on the facts of the situation.
Your whole post comes across as you believe, genuinely believe, that being awful to other people via threats is a natural human state of being.
It isn't.
If my boss ever told me "don't do 'x' or else", it would be the last day I ever worked for that a-hole.