This is not the first time the Red Dwarf crew have interacted with Hitler - in season six's Out of Time, the crew met a future version of themselves that had abandoned all morality and, off screen had dined with the Hitlers. This time line was erased when Rimmer destroyed the time travel device.
This is the third appearance of Adolf Hitler
Also Hitler appeared in Episode Meltdown as a Wax Droid
The United America flag is very similar to the Earth Government flag from the show Futurama, affectionately called "Ole Freebie", where it's basically the American flag with the planet Earth in place of the stars.
The original title of this episode was 'Here No Evil'