They were pretty popular on HN, always been. I know because I participated in a lot of discussions the past years here about all the stupidity going around the cryptocurrency space.
> the popularity of the criticism is increasing with its recent price drop
This is how theories are proposed, vetted and adopted [1]. Bitcoin was proposed as a solution to a set of problems. Over time, the null hypothesis was refined. We're now seeing, with the tide going out, strong evidence to support it. So people are switching sides, or taking a side for the first time.
In Kuhn's words, a paradigm shift was experimented with and appears to be in the process of being rejected.
That seems... expected? Magical internet money is more on peoples' minds than usual at the moment, so it's natural that stuff about it would get more engagement.
But the popularity of the criticism is increasing with its recent price drop.