Meanwhile, that user presumably has the impressive track record of 2 days of posting on HN, making him/her a true expert on the HN crowd.
Seriously, calling people out merely for their account age? Really? You really think that's a valued contribution? I mean, your comment amounts to nothing more than a weakly flung insult.
This is very subjective, but I find people who (again, presumably) haven't been involved in a community who all of a sudden start right off the mark by posting in that community with a phrases like "HN hipsters", to be rude.
HN hipsters dislike PHP.
Divining which is which from posts is a dicey proposition.
I'm not a web-developer (or whatever you would classify PHP as), so I don't feel hit with the remark.
"Hipster" is a term commonly used to describe those who advocate so-called "Web 2.0" technologies like Ruby on Rails, JavaScript, HTML5, NoSQL, and so on. These people openly admit that they dislike the previous generation of web development technologies built around languages/platforms like Perl, PHP, and Java.
There are many of those people here, so it makes sense to refer to them collectively, especially given their typical stance toward PHP. Asking them to revisit their current state of PHP is a reasonable enough request.
Now, "hipster" is also often used as a derogatory term, too. It's quite understandable, after dealing with some of those kind of people. But I don't think it was used in that sense in the earlier comment.