Public perception is influenced by the first reviews published on a new product. If you give a few known friendly writers early access, there will be a few days of nothing but positive reporting. Mainstream media will then pick this up as "overwhelmingly positive" response to the new thing.
Of course Apple has the right to behave like this. Nevertheless, it's good for consumers to know that the early reviews are carefully shaped, so if you want a balanced picture, you need to wait until after the public release.
Apple's target market doesn't give a shit about anybody's reviews of their new products. Their target market will buy whatever new products they produce simply because of the Apple logo on it.
This effect is grossly exaggerated. I'm a self-described Apple "fanboi" but I make sure to read every product review and make an intelligent decision. I'm still on iPad 3 ("the new iPad") and iPhone 4S for this reason.
Of course Apple has the right to behave like this. Nevertheless, it's good for consumers to know that the early reviews are carefully shaped, so if you want a balanced picture, you need to wait until after the public release.