FWIW these days I tag based on the story's overall content and aspects a potential reader would be searching for (e.g pairings), not what any person might be trying to avoid. An appropriate fic rating serves adequate warning IMO.

I've never had anyone yell at me, but if they did I'd just point to the sign over my desk that says "Don't Like Don't Read" and suggest they skip the rest of my oeuvre.