My social circle is full of people that deleted FB. But when I step outside that circle not being on FB is very rare.
I don't think a typical HN participant is deleting their FB account and then telling people to follow them on Instagram.
HN readers know that Instagram is owned by FB.
Another good bit of willful ignorance is that “if you’re not paying for it, you’re the product not the customer” seems to not apply to HN.
The big problem with Facebook and Twitter is a potent mix of incentive for controversy, algorithmic amplification, and groupthink bubbles. These problems exist elsewhere as well, so it's not like it's all social media (eg. television news networks in an age of unlimited media choice), but I don't think HN is a useful example to understand any of the macro-dynamics of todays information culture and political landscape.
The forums that I used to use simply made the top shown comments/threads the most recent activity.
The default HN view is clearly based on some algorithm to calculate what is "worth" being on the front page. I read the high comment topics, and there is a ton of groupthink and pushing controversy.
This is also why the HN effect is even a concept. There are enough people here watching controversial topics to hug a modern website to death.
HN is social media, and anyone who thinks otherwise is deluding themselves.