You got me!

But in fairness, I pretty much always read through a couple comment threads and usually do that until I've read through a few differing viewpoints before ever opening the article just to get my critical thinking juices closing a bit before diving. Also helps me decide more accurately than going by the title alone if the content is going to be of substantive interest to me before I invest the effort and time into it.

I'd probably estimate I actually visit about 15-20% percent of the linked content in the threads I open on HN. But I'd estimate that I probably fully read 80% of the content linked in those select threads that pique my interest so all in all I think it works out. I also don't do very much commenting compared to many on here so it doesn't really matter whether I actually read the source material in this context.