I've read a little about the Nazi persecution of the Jehovah's Witness sect, some examples of which are here :
From the latter, this is interesting :
andThe camp officials discovered . . . that the Jehovah's Witnesses served many useful purposes. One of these was to shave the SS with cut-throat razors. The SS could truly enjoy their toilet, knowing that the razor was in the hand of a man who had sworn to respect life even at the expense of his own. Although such services must have added to their chances of survival, it did not endear them to their fellow prisoners. Jehovah's Witnesses were generally put to work on outlying farms around the camp. They appear to have been the dominant labour force on the land, although there were other workers too. 
Both Himmler and Eicke expressed admiration for the resolve and determination of the group, actually using them as an example of loyalty to other Germans. Interestingly, Himmler, who knew the ways of the Witnesses well, had planned after the war "to bring the persecution of this group to an end, and send them to the East, where as racially pure, upright and abstemious Germans, they would form a 'block' as pioneers of the Nationalist Socialist Community. "
This page is pretty good; not at all IMO a hagiography-type JW site.
Now, a question. Does anyone know of other Protestant Sects grouped into the camps or otherwise singled-out for persecution? If the pacifism of the JWs was so abhorrent to the Nazis, then what of other pacifists like, say, the Quakers? Were there any Quakers in Nazi Germany?
If the zealotry of the JWs was so abhorrent and reason for their grouping amongst the other victims of the Holocaust, then what of other superzealous sects who often employed door-to-door preaching like, say, the Mormons? Were the LDSs persecuted by the Nazis? I know at least a few had to be over there in Deutschland, if only anecdotally, because I remember reading somewhere how the reactionary Governor of Michigan and President of American Motors, George Romney, was a Mormon missionary in the early thirties in Europe (and, I think, specifically in Germany).
Incidentally, the same site also provides this page :
An explanation of Dwight Eisenhower's religious background. Ike's mother, Ida, raised him as a Jehovah's Witness. Doubtless, though Ike had disowned most of the peculiar JW dogma, he knew through the pious Ida or through governmental/military channels that the JWs were being persecuted with the other victims of the Holocaust. I wonder how much extra this fact motivated him. Like anyone moral, he hates the Nazis, but how much is this personal connection to his family's very obscure religious beliefs an influence in his mindset? Interesting.
The whole article is quite good, IMO. I like the description of Ike trying to walk a fine line of not exactly repudiating his mother's religion, but also trying to hide it from the press as it was a potentially huge political liability.
Ironically in a Drew Pearson column published only three months earlier, Jack Anderson said, "Ike is strangely sensitive about his parents' religion. They were Jehovah's Witnesses, though the authorized biographies call them 'River Brethren....'