I generally agree with much Rabbi Barenbaum said regarding the Bible Students who bravely endured the Shoah alongside the Jews instead of compromising their integrity to join the Nazi regime.
However (and I speak as a Jew who lost family in the Holocaust), just as I do not hold the German people of today as responsible or even connected to the Nazis and their atrocities of the past, I don't view the Bible Students/JWs of 1930s Germany as representative of the JWs today.
For instance, the JWs of that period did not believe in all the doctrines now advanced by today's Governing Body. The theology of today's JW would be heresy in the past and vice versa. Some of their teachings remain intact, but the differences are so vast that the connection to the past may not be fair. Ex Witnesses who have left in the 1980s often remark how the actual JW religion dissolved around the end of the 20th century and that the present religion by the same name is something entirely different.
Also the JWs who entered the concentration camps did not do so because of their hatred of Nazism. They were politically neutral out of allegiance to Christ and his Kingdom. They would have rejected any government on this basis.
It just so happens that the JWs who survived the camps not only believed that the Nazi's were under the Devil's control but that the government that preceded the Third Reich was as well as the government that replaced it. While it is not a reason to throw someone into a concentration camp, I will admit, their ending up there was due to the fact that they view all non-Witnesses as blinded minions of Satan. They weren't being heroic against the Nazis as much as they were there because they judged them as servants of Satan just like they do everybody else and every government. They were not particularly standing against Nazism itself.
Finally the Witnesses currently teach anti-Semitic doctrines, and many of these have remained in effect since before the 1930s. They advance a supersessionist ideology, demanding that Jewish converts assimilate to Western culture, and as they have told me directly believe that G-d has rejected the Jews as a people because they rejected and killed Jesus.
The individuals who endured the concentration camps may have indeed been heroic and honorable, but just a one cannot judge all Jews due to the action of a few, neither can the current membership of JWs be automatically compared with the Bible Students that Hitler persecuted.