Every writer faces this dilemma eventually. At some point, you're going to get a bad review. There hasn't been a single written work that hasn't gotten one. The smart thing to do when you get one is to ignore it. Remember that there are some people out there (especially on the internet) who seem to revel in writing negative things. Also, some people just don't share your world view. Nothing you can do about it.
What you shouldn't do is what this guy did. It was his first one star review...but after he engaged, he roused the evil spirits. His book now has over 300 one-star reviews.