We have different definitions of socializing. Commenting on a piece of news or opinions to enhance our thinking and gain knowledge/motivation/ideas, I don't call that socializing. I haven't made any connections through this platform and if I don't check the HNews for a week, I don't feel sad or missing anyone. But that's me. Someone else may be more (in)vested in here and consider HN as an integral part of their social life. I won't judge them.
I suppose there's a subtle viewpoint difference. You see yourself "commenting on a piece of news". I (and presumably GP) see you socializing with the GP, the way you could casually socialize with a stranger on a bus stop.
FWIW, meatspace doesn't maintain social graphs and push notifications - in physical-world social interactions, you're responsible for holding the social graph in your head. Just like on HN :).
Find it weird that more people don't just consider Twitter a forum, if you break it down to what you're actually doing it's pretty much the same as reading reddit threads.
Yet many people have convinced themselves that no, twitter is the real world.
I don't consider those to be social media either.