Did This Rejecting Editor Just Tell This Writer to Grow Up? That Ain't Right....

With all the talk these days for and against YA books, it seems to me that this author is taking his/her life in his/her hands. It says:  "I'd like to see something grown up." Editors are always telling writers what they'd like to see. I think it's playing with fire to do so, unless you really know the writer, or really know what you are talking about.  One time, an agent really messed me up with her "idea" about what my novel should be. Another time I let an editor I trust very much line-edit the voice right out of my novel. I learned some hard lessons. Mostly it's best to be edited by someone who LOVES your work. Here, I think I wouldn't send more work to this person, who doesn't like kid narrators or teenage subject matter. I personally think the comment is pretty insulting. Then again, sometimes it's hard to pass up an editor who asks to see more of your work. What would you do?