It is also the most free eyeballs your product is ever going to get. Start off with an intro paragraph like "Our new widget, available now on Amazon, is the easiest way to toast bread in the morning without starting a kitchen fire! If you like toast..."
Also helps to put the rest of your rant in context. I know nothing about guitars, so I immediately think someone's kid who knows how to play is more qualified than I am to say your product sucks. Why not?
I agree with this 100%. I don't really play guitar and it took me a while to figure what the heck I was reading about. Would also add that this blogpost would be greatly improved by having a link to the homepage.
While I think you're correct, I find it funny that you are in effect complaining that a Hacker News article is NOT an advertisement poorly disguised as an information article or an opinion piece.