I will put in reasoning I didn't see for thinking JW had the truth. They didn't celebrate what we know are pagan holidays. Instead of teaching a person goes to heaven or fiery hell when they die, they teach what the Bible says about the condition of the dead. Some of your have mentioned the JW and being persecute by Nazi and this is true;but from what I have gathered ( info can be found on JW facts -letter to Hitler ) at first they wrote and said they held the same values as Hitler, but once they didn't get the desired outcome, they "punched the bear" and therefore brought on a lot of persecution. ( But the JW r/f aren't taught that! )
I do think there is some truth in the teachings of JW, but it is so with other religions. They are still part of Bablyon the Great and we are told to get out.
Then there is this thought that I recently come to realize -saw it in a youtube comment: 2 Tim 3 :5 having a form of godliness, but denying it's power. Have nothing to do with them. ( I used to think this just about individuals, but I think it fits the religions as a whole.) This about all the hidden CSA in religions...that is certainly denying godliness. Not to mention other corruptions church members get involved with.