Complaining that something is generally behind a paywall is different from complaining that a site centered around widespread discussion of content frequently promotes content behind a paywall.

I'm fine paying for content, but the content rarely belongs on HN, because it is insane to say to the general HN reader "Hey, here's an interesting article. Pay to read it before you have any idea of what it is about beyond the title".

What happens when you have pay-to-read content on HN is that no one actually discusses the content of the article, and only discusses general topics relating to the topic of the article - making for lower quality discussions.