Your criticism is, on the surface of it, very relevant. The superficial hypocrisy of my earlier statement would really serve to hurt my credibility if this were a willfully polarized ideological bubble.
The difference is that an on-topic reply to an on-topic comment on an on-topic post diverges as part of an ultimately topical and natural progression, whereas starting with a polarized and ideological post that has little to do with technology, startups, or spontaneous cleverness only serves as an opportunity to reinforce the poster's ideological outlook as the new normal; that is, to move the Overton window.
I myself have been guilty of this. I told a friend of mine that I'd gotten some traction with a blog post about not getting hired by dropbox, and he asked me to share a really juvenile idea he'd had for protesting the TSA. I did it; the post was poorly received, and the community spanking was enough to remind me of what effective participation in a pseudonymous social news link aggregator looks like.
That being said, neither did I start this conversation, nor was it the sort of ideological shouting that drowns out the interesting stuff. The grandparent has a good anecdote about the poster's experience with retirement planning and raising a lot of children, and it makes a point with which I happen to disagree. I voiced my disagreement without attacking the comment or the person who made it.
Ultimately, I disagree both with your implied disagreement with my original point and with the validity of your rhetorical question, but I don't disagree with the topicality of your attack and therefore I don't think your comment deserves the downvote it has at present.