The downside to becoming a published author is that, like any artist putting their work on show for public display, your work will be reviewed and criticised. There will always be bad reviews and it’s the nature of most humans to allow the negative stuff tends to linger more than the positive. As a writer you have two options; you can let it get to you or you can accept and move on. I recommend the second option. Remember, you can please some of the people all of the time and you can please all of the people all of the time but you can’t please all of the people all of the time. What you definitely should not do is respond angrily. Your readers and reviewers are entitled to their opinion. Modern technology allows for easy expression of that opinion. Making excuses, blaming others and being personally critical is not good for business, no matter what business you’re in.
Case in point: http://www.guardian.co.uk/books/booksblog/2009/dec/22/when-authors-attack