I have seen how upset people have become recently when reviews are not what they wanted. I was very shocked as Reviews of course are opinions.
My opinions differ then others and I am sure you may not agree with how I rate items at times. Nothing a reviewer writes should be taken as a personal attack as it isn’t meant to be.
Yes there are people who troll and deliberately devalue the hard work that an author has put into the book. Those are few and far between.
I have also seen a lot of discussions that as a reviewer if you dislike a book should you review. The answer to that for me is simple, Yes a book should be reviewed even if you don’t like the material. I have given 1 and 2 star ratings to a book that didn’t live up to expectations and I will continue to do so.
Remember that if you are asked for an honest unbiased review that there is a way to say you didn’t enjoy the book without hurting the authors feelings. I try to show what good points there were and also what didn’t work for me. I try to show positive as well since it makes me feel that it wasn’t a complete waste of time. On the odd occasion that I can’t finish a book I will not review those ones.