If it's that enjoyable and well-made, why not set it on American or any non-Axis submarine and avoid all the politcal trouble? The U-Boat war against Allied and civilian shipping isn't something that really needs to be glorified, in my view, especially when every game following the original Silent Hunter has been nothing but U-Boat sims. Enough, already!
One of the best things about simulation type games, to me, is the way they can sort of put you in someone else's shoes for awhile. No, I don't agree with the Nazi philosophy, but the guys who went out in the U-Boats suffered horribly for their country and portraying things from their angle allows us to see things from that perspective, if only for a little while.
Besides, our own campaign against Japanese merchant shipping was just as ugly and brutal as their campaign against us. We sank ships without warning, machine-gunned survivors more often than the evil Nazis, etc etc. Sure, you can argue that the cause is better, but our actions, while neccesary for our survival, are no prettier than the
Kriegsmarine's. If you're gonna argue that we shouldn't glorify such things, then there shouldn't be ANY war-oriented sims.