The answer is simple. There are two types of people who write these reviews.
Bad literary critics of young adult novels are full-fledged adults who are judging the books from an older adult’s point of view. These are the book-bashers you refer to. The majority of these people are condescending, self-proclaimed pundits of literature. They get paid to write about books and the more people to read their column, the more their employer pays them. And bad news sells whether it’s true or not. Popularity is more important than accurate fairness.
Then there are the good guys who fairly judge books for children and young adults. Newbery and Caldecott immediately come to mind. They are the paragon of the industry. Follow their recommendations in your preferred genre and you’ll find what you want.
That said, this is the most important thing to remember and practice. Be your own critic and decide for yourself is a young adult novel is good or bad.
Always keep in mind that literature is an art. Every piece of art ever created is yours alone to interpret, analyze, and to like or dislike. It’s the artist’s job to create; it is the viewer’s job to judge the value. Plus, there has never been a “you” before in human history. No one else has the right to tell you what you can or cannot enjoy.
Hey, if you ever have a poetry teacher say, “This poem means….” Drop the class. His responsibility is to assist you to interpret and analyze for yourself, not to thrust his own ideas upon you. What it means it you is what it means.
Besides, chances are you will not like everything written by your favorite author. similar to most English teachers, I really like Shakespeare, considering him to be among the greatest playwrights and sonneteers in our language. But the guy wrote some real stinkers too.
Think about your favorite musical artist or performer. Most often there’s that one song on the album that you always skip over because you don’t like it.
In short, listen to no one except yourself. Those critics are reading these books through the eyes of their paychecks. Who has a better and more honest view, you or them?