I don't disagree on the QA staff point, but any new product, no matter how well designed, will have problems. And this is across anything that can be bought and sold, software, devices, ideas... nothing is ever perfect first time.
A related concept is that no amount of testing is ever going to cover every corner case. I mean, for the sake of argument, let's say this guy's iPhone hasn't been updated in who-knows-how-long and is running an OS that's five years past its sell-by date. It's probably next to impossible to buy an identical phone to test with, but their software needs an update that was introduced two years ago, and there's no way around it. This all could have been conveyed in a calm and pleasant (and constructive) forum thread without resorting to name-calling on anyone's part.
I get that first impressions stick, make no mistake, and having the product fall on its face as soon as you get it out of the box is one of the worst. To a degree, users have unrealistic expectations (I'm a developer-turned-engineer), but companies are guilty of that by letting their marketing divisions claim perfection to the point of making your morning tea the moment you open the package.
Just saying that, yes, an out-of-box experience gone bad is not what you pay for, but a polite email to the company or seller can often resolve it quietly and calmly, and in the extreme case, they'll offer a refund. I've dealt with several bad buying experiences this way and usually end up rewarding the seller for doing their utmost to make things right after a firm but professional email exchange. No need for cursing, just telling the seller you are unhappy. Of course, being more technical than the average, my expectations are probably much closer to reality from the outset. Most people buying into the IoT market seem to be average Joe's expecting magic.
If the company had responded correctly, this could well have been a positive outcome and the circumstances that caused the initial complaint nullified, so nobody else has a similar out-of-the-box experience, and the one-star review becomes obsolete. In that scenario, I as a seller would be extremely eager not to let that one bad experience spread and taint perceptions of my product.
Of course, that didn't happen here. The company is way more at fault, no question, but the buyer had no reason to curse a device that didn't live up to his expectations, however unrealistic they are, until the company has had a chance to explain themselves (whether they take it or not). However, now it's all blown up. As for whoever's behind that official forum account, I sincerely hope they're either fired, or if it's the boss himself, his product probably deserves to fail. No room in this world for two Elon Musks...