If I recall correctly, the endangering information was not originally published by Wikileaks, but by other journalists (the decryption key was written in a book or something, my memory is fuzzy on this); and Wikileaks only published the whole thing once the cat was already out of the bag.
To sum this up, they were putting the redaction work, but someone else failed to, and at that point it was too late.
The material was shared with The Guardian and several other (including prominent US) media outlets, they are the ones that published it unredacted. Never was there any proof provided that those articles caused any harm to any personnel at any point in time.
Those media outlets that are in fact guilty of what Assange/Wikileaks was accused of jumped at the first opportunity to throw Assange under the bus.
To sum this up, they were putting the redaction work, but someone else failed to, and at that point it was too late.