Continuity mistake: When Klinger imposes himself between Oksun Li and Crosetti, he puts his hands on his hips. When Crosetti gets up, Klinger gestures with his hands which then drop down on either side. A split-second later they're on his hips again.
Continuity mistake: In Rosie's Bar, the lettering reading "GI CLASSY" is in thick letters. From the outside, the lettering is thin.
Continuity mistake: When Mr's Li first threatens Klinger with a pitchfork in his office, it has four tines. A close up shows a completely different five tine fork. Then back to the first one.
Answer: Even an Army field hospital would have SOME weapons for self-defense if the enemy attacked. What's meant is that it's not a combat outfit, and therefore wouldn't have enough weapons to actually attack anyone. (It's also mentioned a few times that the Officer of the Watch is supposed to carry a pistol at all times, but Hawkeye refuses to do it when he's in charge and Colonels Blake and Potter don't enforce the rule).
Captain Defenestrator