That's just stupid. Nobody ever in world history has ever described prison as fun.
True enough, I'm sure, but POWs didn't really lead a prison life. They did farm labor and perhaps factory labor as well; even got paid a bit, I think. One of my instructors in Berlin had been a POW. He concurred that he was very well treated and held warm memories of his time here.
You obviously have never worked in forensics where many that are released do everything they can to get back in prison.