How about instead of using a crappy word that attempts to tar a nebulous ill-defined group of people, you just point out the issues you have with it. No need for the "hipster" straw-man, as far as I'm concerned, and I agree with your points. "Hipster" is over-done, and from where I'm sitting those who use it pejoratively come across as elitist.
Like I said in the comment you replied to, if you have a better term, please mention it here.
I don't think that these people, or more specifically their attitude and their approach toward software UI design, are "nebulous" nor "ill-defined". It's extremely easy to identify incidents involving them: Windows 8, GNOME 3, Firefox 4 and later, this new version of Google Maps, and the Slashdot beta website, among others.
There are some common traits we see with these cases:
1. They hijack an existing, well-established software product.
2. They throw out years, if not decades, of accumulated knowledge and experience.
3. They usually come in with little to no relevant experience themselves.
4. They consider appearance far more important than usability, efficiency or productivity.
5. They create a design that's obviously flawed in many different ways.
6. They refuse to accept or even acknowledge these many flaws in their designs, no matter how loudly long-time users point them out.
7. They release their changes into the wild, often forcing them upon users who absolutely abhor the changes.
8. Their design efforts drive away more users than they could ever hope to bring in.
The fourth and sixth points are the key ones here. They are the very essence of the "hipster" attitude, regardless of whether we're talking about clothing, food, software UI design, or pretty much anything else they're involved with.
