You are right. I'm updating in favor of "Tom Riddle" showing on the map. Still not convinced because when Dumbledore says "Show me Tom Riddle" the twins don't go "Hey, that's the guy that keeps popping up!". That might have happened off screen, but we don't see any evidence that it did.

EDIT: I have re-read that part, and Dumbledore waits until he is alone in the room to say "Find Tom Riddle".

On the other hand, I admire the poetry where having a taboo on the name and story of Voldemort ultimately dooms you, just because you didn't want to remember and talk about the bad things. Harry even talks about this in one of the early chapters, I believe.