How about you just point out that it the story is anecdotal? There's not any call for telling anyone to "please refrain" from their comments if they aren't abusive.

For the record, I'm not crash hot about this anonymous anecdotal evidence either. I think that eating unhealthily is bad no matter whether you are on a farm or not. But to tell someone to be quiet? That's a losing argument - refute it, don't silence anyone.