"Bars and Stripes Forever" portrays a not-so-gritty prison full of gags. Of course, now that the United States has 2 million people in jail*, this isn't exactly a source of humor. The Attica uprising brought attention to the conditions in prisons, although it looks as though things didn't change much thereafter. In "The Big One", Michael Moore interviewed an ex-con who'd been forced to take calls while in jail. The majority of the prison population is black and Hispanic - their time behind bars tends to keep them in poverty - and large numbers of people in the '60s were imprisoned for having a single marijuana seed.
But I digress. I certainly laughed a lot at this cartoon, as I have at practically every classic Warner Bros. cartoon. Directors Cal Dalton and Ben "Bugs" Hardaway ran what had been Friz Freleng's unit during the approximately two years when Freleng directed the "Captain and the Kids" series at MGM; after MGM canceled it, Freleng returned to WB and got his old job back. Early on, Hardaway had drawn a picture of a rabbit (calling it "Bug's Bunny"), which of course became WB's most famous cartoon star.
*The country with the second highest prison population is China. Imagine that: a police state with four times the population of the US has fewer people in jail. Maybe most people over there know how to stay in line.