Hrm.
I sense some hard feelings there.
I will note that while your grandfather claimed to have experienced treatment far below that mandated by the Geneva Convention, I'm not certain that it was officially allied policy to do so...or at least, not an officially espoused policy such as Germany actively pursued throughout the war in the way it treated some members of it's own population, and various captured "lesser people" I think the correct term was "Untermensch"...right?
The "Final Solution"....may have coloured how the allies handled some of their prisoners, no? Oh, and that WAS an official policy of the German Government of the day.
In the end, your grandfather obviously lived, which is better than the between 6 and 17 million (depending on the wikipedia math...
http://en.wikipedia.org/wiki/Holocaust )
There's a thin veneer of civility in our world...the holocaust was a mere 67 years ago....and events like Rwanda and Bosnia provide even more recent examples of how things can go off the rails.
I don't accuse anyone of participating or condoning those atrocities, but reaching back across the years and saying that it was policy to mistreat German prisoners....well....if you live in a glass house, don't throw stones.
NS