I have to confess to being puzzled about a lot of things. No, as a freelance writer, you wouldn't be the editor - not of the New Yorker, anyway. So whoever wrote you that email was probably someone with a sense of entitlement and resentment - certainly ignorance.
I've had a lot of them in my life.
I also took the time to read your piece in the New Yorker. Along with San Diego's Reader, the style does nothing for me. I don't have the patience to read something that is irrelevant to my life. So I'm probably coming in from the back door here.
I haven't seen the movie, and I have no intention of seeing it. I neither like chess nor am I particularly impressed with people who struggled in life. My own struggles (various disabilities and chronic abuse) were too intense for me to be impressed by anyone else's. So, again, I might be speaking from ignorance.
My conclusions are:
Jealousy is one factor. You were published in the New Yorker. The other factor is you probably trod on the toes of someone who swooned about the movie.