I’ve done quite a bit of reviewing over time, and ended up stopping because, whilst it is nice to be able to give suggestions and advice on way a for people to improve their stories, many people who ask for reviews, don’t care to listen.
I still remember the first one I did, and I explained things which I found needed improvement, the story’s progression was too fast and clumsy and made little sense, and after reading the story and spending ages on feedback, I was told that they wanted it that way, and they liked it, then given the brush off. It was a total waste of my time.
Since doing more reviews, I’ve come across other writers with that attitude. It seems many use free reviews especially, to just gain reads and exposure with little respect for the time it takes to not only read, but advise people on improvements for their work. Depending on the depth of feedback you provide ( I tend to cram as much in as I can, to be thorough) then this can be a seriously lengthy process, so this attitude can be frustrating.
I definitely believe honesty is crucial, it’s what’s being asked for, whether they like it or not in the end. BUT, it should be delivered in a respectful, polite and encouraging manner. Not brusque, callous and critical.