The thing is that the educated buyer sees that even the people not smart enough to understand the technology before trouncing it in an online review get to post their thoughts without it getting wiped, so you know that the knowledgeable who post either good or bad get on there also. On popular items, it is more info to sort through but with more reviews, you can pretty quickly get the picture on what common praises and issues go with that product, breezing by the trolls or flamebait. I also like the feature on Newegg where you can "sort by helpfulness" so that you can see the reviews others have already noted were helpful to them, both positive and negative.

At least in the USA, unfair and deceptive commercial practices are forbidden by the FTC Act, and deception by omission is still deception.

Quoting from the FTC: "Section 5 of the FTC Act prohibits unfair or deceptive acts or practices in or affecting commerce. The Commission will find deception if there is a representation, omission, or practice that is likely to mislead the consumer acting reasonably in the circumstances, to the consumer's detriment."

The practice of publishing only the positive reviews, without disclosing that fact, appears to be an ommision likely to mislead a consumer, and would therefore be an illegal practice. You didn't say whether the merchant is based in the US, so this may not apply, if they are ouside of US jurisdiction.

Doing this would also open Apple up to a massive anti-competitive lawsuit, very similar to what Microsoft was hit with, especially since they are singling out one particular competitor - that's a big no-no for our anti-trust laws (which don't necessarily require a monopoly to apply, though Apple does dominate the music player industry).

What you're suggesting is that Apple quite literally shoot themselves in the foot.

Giving a troll any sort of encouragement makes me a bit nervous but I agree. Something akin to movies - why write good dialogue when it it so much easier to blow something up?