this seems like quibbling unique can be used in the world loosly in many senses It was unique in being founded on the day it was founded for example or in having the exact mix of jews and non jews it may have had But in terms of an encyclopedia which tries to be accurate it s a much stronger claim than the evidence warrants If it was not the only organization if its kind it is not unique it any real sense to say it was unique as being the only Jewish rescue group formed by the right wing as Boodles says may well be accurate but could be read in a much more negative sense than I think he intends Best to not use the word Its hardly critical to the point