I mean… we could argue that 'till we’re all blue in the face
of what a good and fair critique should look like based on the dictionary definition, but there’s a ton of outside factors to step back and consider in terms of any type of feedback.
Maybe not enough time to time out something that’s paragraphs long. Maybe they feel that their insight isn’t valuable or worthwhile or just a rehash of what someone else has said. The list goes on and on and on.
Ultimately, feedback is subjective since it’s based upon opinion and opinions aren’t something that can be proven to be right or wrong.
And just to double down on my previous point, you could think of giving feedback in two very extreme examples as either being a drill sergeant in an army and screaming in someone’s face or just glossing over what could be improved, reinforcing that nothing needs improvement and that everyone who thinks so is just mean.
Ideally, feedback shouldn’t on either end of these two extremes for obvious reasons.
If your feedback mimics a drill sergeant, the author will ignore you, think that you’re the problem, and will probably never listen to you from that point forward. If your feedback is just sweeping everything that could be improved under the rug, you’re basically helping them put out a “faulty” product and you’re not helping them improve to be a better writer.
It’s been brought up a couple of times, but I’d like to chime in and say a 5 Star rating system is not a very good system to begin with for various reasons. The most relevant to an author is that it encourages buyers to do the bare minimum (just leave a star or several) without going into detail as to why they gave the product that rating.
The 5 Star system is most appropriate for products that are tangible i.e. DVDs, a phone, etc. since it’s probably easier to understand why you gave something a 1 Star if the product had a giant crack down the middle of it.
And let’s not get started on customer by customer “standards” of how something should qualify as a 1 Star or 5 Star. 



