HN's criterion is whether a post is intellectually interesting, or more precisely whether it can support an intellectually interesting discussion. What's nice about that is you can decide it by looking at the article itself, and the thread—you don't need to know nebulous things like the intentions behind the post. I'd say the current post clears the bar fairly easily. Here are a couple of past explanations about this, in case they're of interest:

https://news.ycombinator.com/item?id=20186280

https://news.ycombinator.com/item?id=22871601

As for negative/challenging/sceptical: that depends on the quality of the comment. Thoughtful critique is always welcome. Shallow dismissals and snark are not welcome—not that the target of the criticism always deserves better, but the community deserves better.