Compare that to the millions of "German Christians" - Protestants who found they could easily reconcile putting the swastika up next to the cross.
I think this is a silly argument. The Communist partisans also bravely fought the Nazis. Is that now our standard of theological truth - if so, then militant, class warfare atheism is awfully Christian.
The JW religion is NOT a Protestant belief system. It is much older than that - it is a recapitulation of a 1st century heresy. The church stood firm against its denial of the divinity of Christ back then, and we must do the same today.