Why did Colonel and Rose joke about Raiden preferring a fantasy setting instead of Shadow Moses? [MGS2]

This happens at the end of the game. AI Colonel and Rose mention that Shadow Moses was chosen as a template for the S3 plan because of its harshness. Rose then jokes, "I wonder if you would've preferred a fantasy setting?" and Colonel chuckles.

This sticks out to me, being a huge fan of fantasy games. I wonder if they just took a shot in the dark and it happened to land on me. I get similar feelings to Psycho Mantis reading our memory cards and mentioning the games we play.

Is there something else to this quote? Does anyone have any ideas on why it may have been included?