There are contexts (say, the comments section of a story on foreclosure) where "I don't buy a house I can't afford" would be a full-on raging asshole thing to say. But you went further than that:
"I also don't understand how people chose to have a full-time job...AND kids"
You clearly implied that holding any full time job and having kids was irresponsible. Because "I don't understand how [something about mores]" is a construction that American English speakers use to point out things they consider irrational, dumb or otherwise undesirable. You even anticipated that your comment would make people mad ("before you reach for the downvote button", "not judging anyone"). Because you went a good sight further than "I don't buy a house I can't afford." I think my initial judgment of "naive and/or jerkish" stands.
Anyhow, no "jerkishness" intended, this was mostly an observation after yesterday's thread "Where do you find the time for side projects?" https://news.ycombinator.com/item?id=7117131 where many parents chimed in on how they squeeze family time here and there between working and juggling side gigs, great for them, but I could not do it without burning out, and I would owe it to my family not to risk that.
So long as I want to work long hours and risk my livelihood building things on the side and use my free time hacking, fine, I'll be on my own. The day I'll be able to afford a family (money-wise but particularly time-wise), I'll do so.