It's not really ok to bring someone's personal details into a thread and ask them to account for their choices. It's good that you were polite about it, and curiosity is a good intention, not an attack. Still, this is a questionable thing to do, so I don't think you get to respond rudely ("Chill out") when questioned about it, or react like what you did is normal; it's not.
This hasn't to do with culture or coddling, but with preserving HN as a place for civil discourse. Arguably nothing on an internet forum rises above trivial or "matters in the slightest", but that doesn't mean you get to violate the rules, which you're doing increasingly. Please stop.
His Github username is also the same as his Hacker News username.
Chill out.