The expanded universe materials are very strange for me in that they state the interrogation droids of all kinds, at least the imperial ones, were designed specifically to extract as much information as possible with as little physical and psychological damage as possible and in the next line they say that those things had bone fragmenters and even carried firearms, sorry, blasters, of course. Does not that seem at least a bit irrational? Did you ever see a blaster on this thing? Did you ever see anything but a syringe and a single arm that I suppose was designed to hold ones hand firmly while injecting something on this thing? I think its main purpose was still a sort lie detector and a medical assistant.

Is the radio drama explanation considered the canonical one?

Also that dialog from the drama lets us think that the droid was officially illegal.

The fact that ewoks were going to eat somebody is not the same that they were good military able to effectively take down imperial stormtrooper squads and armored vehicles for me.