Yeah, the double standard... We are here on hacker news probably because our parents let us freely explore computers and the internet. "Screen time" wasn't even a concept. Most friends I talked to had really off-hands parents as well, parents were rarely involved or interested in what the kids were doing. Glad I didn't have overbearing parents who limited my technology use to the radio and LPs.
Well a lot of people, which must include many parents, cannot limit their screen time so is it any wonder they fixate on this with their kids?
My guess is this type of screen addicted user is overrepresented among internet commenters as only a small fraction of the population actually comments on anonymous/pseudonymous forums. Which is why it attracts so much energetic negativity on HN.