I look at any author's work like it is their baby. I wouldn't walk up to a parent on the street and say, "Wow, what an ugly baby!" Likewise, I wouldn't tell an author that their novel is horrible. As an editor, I gave suggestions to my authors about certain things. If the conversation between characters was flat or sounded forced, I would let them know. If a description was so long that I forgot what was actually being described, I would let them know that as well. If, I come across a book I can read but it just didn't really do it for me, I may not rate it at all. I might just say it was an okay book and leave it at that.
So, there you go. This is why you won't find bad reviews here. Comments and suggestions are greatly appreciated! Happy Reading!!