I do agree that once you start writing to someone else’s style, it’s not your work anymore, really. And it feels awful to be told how to write your own work.
I am going to make a confession here. When I was brand new to publishing my work, as opposed to not so new which is where I am now, I let an editor talk me into major changes to a novel. It was her style, not mine at all, but she assured me it would work, and my book would sell, even if I felt like I no longer quite recognized one of my main characters. She was enthusiastic, and I know she meant well, but… I wasn’t really happy with the changes although the novel went out with them.
Long story short, that publisher went under, and I’m now working with a new publisher to get the books back out there. The first thing I did was strip all those edits from the second novel. Every. Last. One. I’m enormously happier, and I finally am beginning to feel some enthusiasm for continuing the series, since I have my character back. Oh, and I scrapped the contractions in narrative. Not my style at all unless I'm writing first person POV (which I only do when seriously tipsy… :D)
My response to the reviewer would be along the line of thanking them for the review, and suggesting perhaps they try their hand at writing a story in their style, since the world needs more writers. Or something pleasant to start with, anyway. I prefer to try being nice first, but that’s me, and my definition of nice varies depending on the situation.