I think to find it funny you have to have had experience of the Services in the 1960s and early 70s.
I was part of the Air Training Corps back then and found the show hysterically funny: I'd met people who matched most of the characters, especially the dimwit Officer...!!
But it is Homophobic, Racist and most other things that melt snowflakes, so sadly it will never be shown by the BBC, despite bing a good example of social history.
