HN, as anywhere, has an echo chamber, sure, but it also does have better dialog even around the sacred cows than others (i.e., perhaps the biggest one here, "startups are great!", is balanced with "They're lotteries. Go to a FAANG if you want to get rich, and anywhere established if you want better work/life balance")
You get downvoted because there’s actual evidence the interview process is deeply flawed and essentially a proxy measure for tolerance of anxiety (and of course raw intelligence), but does not correlate well to actual performance. You shouldn’t necessarily be downvoted, especially since there might be some merit to the overall thrust of your argument in defense of the tech interview. However at some point it’s entirely possible you sound like the person espousing homeopathy to the local skeptic club.
Free exchange of ideas does not mean each is given equal weight. That’s only a lie those who spread misinformation and peddle pseudoscience propagate.