You might find it useful to read the HN Guidelines [1]
"On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity."
"Please don't complain that a submission is inappropriate. If a story is spam or off-topic, flag it. Don't feed egregious comments by replying; flag them instead. If you flag something, please don't also comment that you did."
So any article under the sun is relevant for HN? That's definitely not the case as mods frequently remove posts, and as much as they would like to be, mods are not arbiters of intellectual curiosity.
The guidelines are vague, but the site was still never intended to be exclusively about engineering - hell, initially it was called Startup News.
I find it useful to look at the submissions by the site's creator[1], before he passed over the site's management to others, back in 2014. As you'll see, it actually has very little engineering content, and on the contrary, has many articles from mainstream sources.
I'm sure HN has ebbs and flows on the ratio of engineering articles, but it was never supposed to be dedicated to those; maybe you just joined at a moment when the ratio was bigger.
"On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity."
1. https://news.ycombinator.com/newsguidelines.html