Whether you feel funny for this joke or not is totally up to each person's sense of humor. I feel it was a joke because of the following components:
"Military" and "sanitary" have very similar pronunciation indicating the need to listen carefully for what Jerry is claiming. I was trying to ruin Jerry's plan to lure the lady. Second, I want to stop Jerry from bragging his career, not bravery in the battle field but just some clerk work on a ship. And this concern of not respecting American veterans is indicated by the title. Hopefully this helps. Anyway, what I'm doing is to entertain everybody here in this forum and would love to see everyone is laughing!.