All I want to do as a reputable business is serve you, my customer, as best as humanly possible. Amazon denies me that opportunity. And, if you think about it, they also damage you by not allowing direct private conversation with the seller. Why? Because often times it is impossible to help you due to the fact that it all has to be in public. Sellers are not allowed to post links or email addresses. Neither are you. And nobody would want to do that publicly anyhow.
Product reviews isn't where customer service should happen. It isn't the right place and it doesn't allow for proper communications.
Questionable competitors could (and do) use this public forum to bait a seller into responding and then start a horrible flame war that cannot be controlled. Amazon does not offer any moderation, editing or even the ability to delete false or damaging statements made in product review comments.
Their approach to dealing with grievances, small or large, is a great example of non-customer-centric thinking, despite what cool-aid Amazon management might be drinking.
It looks like posting email addresses is possible? I have also seen phone numbers posted by sellers in cases like this before as well.
I agree with a lot of your points, but not this one. As a buyer on Amazon, I love seeing sellers respond politely to reviews. I've seen sellers offer refunds, repairs, and other things a few times and this has been hugely influential in the level of trust that I had in them.
On a few occasions, this has made it obvious that the original reviewer wasn't really being genuine or was just being overly critical as well.