I have always read a lot, and in recent years, I have begun to write a lot. In the last couple of years, I have increased posting reviews on books I have read. I can see the need clearly, now that I am an Author as well.
I am not what you would call a traditional writer. I try to write in a conversational manner, making it easier for the Reader to read. I write about subjects that interest me, even if they are limited in popularity. My protagonists tend to get into intellectual rather than physical fights.
All of these things means that a traditionalist who reads my work may have bad things to say. Should I change what I am trying to say? I do not think so.
Over time, I have come to realize that when I review a book, I should review it for what it is, not who I am. Romances are not my cup of tea, but if I review one, I will try to compensate for my dislike of the genre. If I can read it with ease and understanding, I should not grade it harshly for style and grammar. The world is changing, boys and girls, and the occasional 'their' where 'there' is needed is the order of the day.
By all means, we should be honest in our appraisal of books we read, when we review them. Honest, and critical, but not harsh and mean. The Golden Rule applies to writing just as much as it does to everything else.