blondie: I was not alive then but my jw relatives from that period were shocked that they were prepared to hurt people and not depend on the police.
I wasn't either but I imagine the justification came from them viewing it as "self defense". One of the WTs from 1939 said this:
It was only after Rutherford took his cane to the grave, and the WT found out that it was more advantageous to play the victim card rather than pursue Rutherford's militant tendencies, that the passive, non-violent approach became the norm. Not only that, but they likely found out that canes can be pretty ineffective in the face of military power.