Since its effect is directly proportional to the cost of the purchase in question, it would make sense that relatively expensive objects, such as smartphones and computers, would trigger a correspondingly stronger negative reaction to criticism of said product.
Saying "people defend the products they buy, sometimes wrongly" is not in any way controversial, and wasn't (in my opinion) about your comments.
Seriously, not everything need revolve around your one comment. FFS.
Dissonance model has been shown to not be proportional to price. Which is intuitive as you see fervent defending of brands for products such as beer, wine, websites etc which are relatively low cost or have no cost to the user.
"Post-purchase rationalization", even if we are to take the sketchy "studies have shown route", goes for major stuff, not for each and every fault or bug in a bought product.
People ARE able to talk ill about their products, and in fact Mac and Windows and Linux users speak ill of their systems each and every bloody day. We even have mottos, like "FTFF".
Given that we have a plurality of OS X users on HN (according to the last poll), it's not surprising that post-purchase rationalization is a common response to such articles.