For the same reason Google's and Apple's results also reach the front page. HN users upvote the posts. Maybe it's because Meta is one of the largest tech companies in the world and for many people their results are interesting news.
Because it’s one of the biggest tech companies and its results foreshadow earnings for other tech companies. Just look at the after hours price movements of most of the tech stocks.
Man, I bought some stock a bit after IPO, it dropped a bunch, and I idiotically sold later at a slight loss in 2013 after people all around me constantly went on about how they would never make money. It's now worth 17 times what I sold at.
I also remember around Google's IPO people questioning how they'd ever make money.
I used to pay a lot of attention to the comments of certain HN users who made well reasoned but (with the clarity of hindsight) mostly doomer predictions about various topics. I wish I hadn't listened to them.
i think i sold my apple stock at $10/share. I also had my finger on the buy button for AIG at around $1/share in the depths of the financial crisis but didn't do it. Now I just stick to code, my 401k, and company RSUs heh.