Why do I have the right to write the post? Simple. I read tech journalism. I read newspapers, blogs, magazines and much more. Consumer feedback from a consumer.
Lack of evidence? Oh god, it's like the air we breathe. Every time there's a product announcement, the amount of completely bullshit reporting, completely oblivious to what has gone before drowns out everything else.
My quiz covered programming, sure. It also covered software more generally, security (WEP vs. WPA) and Internet standards. The programming questions led up to a question about the App Store, which is kind of a business question really (if someone comes along and says they'll build you an amazing iPhone game in PHP...).
As I noted in the comments, I'm not expecting perfection. You don't have to be able to answer all the questions: but I've met far, far too many people who write about technology for a living and not only couldn't give an answer if I asked any of those questions but wouldn't even have a clue what I was talking about.
Do I expect every tech journalist to be able to answer all those questions? No. Am I being unreasonable in expecting tech journalists to know a smidgen about tech? Not at all. No more than if I expect people who write about politics to know a little bit about Parliamentary procedure or the democratic process.
Do the tech journalists which fail my admittedly very hastily made-up quiz/rant know about hardware or electrical engineering or the complexities of business or political and environmental regulation? I don't know. They seem to know a lot about social media, which seems to stand people in good stead for writing about technology for some reason.
And finally, there is a pretty fucking significant difference between being someone who "isn't worth listening to" to and being paid to write about technology. I don't know anything about wine – if offered a column writing about wine in a national newspaper, modesty would forbid, right? The reason you get elevated to a paying gig writing about technology could have just a little something to do with knowing something about the actual technology.
If only so when someone from a technology vendor comes to you and says that the brand new thing does ten octoflops with added HTML5 social media wigetization, you know what the fuck they are talking about and can call them out on it if it sounds like bullshit.