This is a great read because I'm sure it's something we all (authors) struggle with. My stories are an investment of my time, my creative energy, personal parts of my life, and so on. So yeah, when people are mean, it sucks. I won't deny it. It's hard to not feel personally attacked since all my stories are personal to me. One thing I've noticed is the comments aren't so much about not liking the writing as how the reader is feeling. It's an emotional response when something isn't going the way they want or a character they love is being hurt. They lash out. Sometimes it's simply a testament to great writing, which will be voiced at the end.
And sometimes they really just don't like it.