There are many authors who can't take bad reviews. This trend is getting more traction with self publishing being so easy. I know I'll get slammed for saying this, but new writers today haven't earned their stripes in the publishing world. Some of those striped include learning how to take criticism and growing a thick skin.
In reality, it's one person and one opinion. Not everyone is going to like everything. Get over it.
In fact, I don't mind negative or poorly starred reviews because that person tells me through their review what didn't sit right for them. If more than one person says the same or similar, I know it's something *I* have to work on as the writer. Those comments make me a better writer, so I'm grateful for them.