1. It's not your website, why spend so much time and effort on dissecting the issue? If one did this for every webpage they visited it'd be a more than a full time job.
2. Does it really look like Hacker News has had any serious development effort poured into it anytime recently? What incentive does YC have to put time and money into a forum that generates zero revenue?
3. Do we really expect web browsing to be pleasant on a 3 year old budget smartphone with a Qualcomm 617?
The Moto G4 Plus is solidly in the bottom 25% of phones listed here: