Genuine POWs felt the same way about “Hogan’s Heroes”.
Hogan's Heroes was created in order to mock and belittle the Nazis. Jews like John Bannon, Werner Klemperer, Robert Clary, and Leon Askin participated in that series specifically to mock the Germans. It was their revenge, so to speak.
I don't know about MASH, but considering the people involved in creating/running the show, I would doubt that it had the same purpose.
In the 60's I grew up on SAC bases. Many of the aircrew members were former POWs in Germany.
They were not amused by Col Hogan and his comical captors.