When JWs go from door to door canvassing, they are sales people. They are selling a life policy or an ideal. To buy into this policy will cost the buyer his or her life's resources.
If the policy is genuine and what it promises to be then they have bought wisely. If the sales people have lied, whether unwittingly or not, the buyer has been duped. If a sales person sells a bogus insurance policy, the customer has been duped. They chose to believe in something that was presented as genuine. They willingly bought what they were assured was a genuine life policy.
The deception is the fault of those who lied to the sales people who also bought into the policy, and in turn passed on the lie. If the policy is not genuine the fault cannot be placed on the victim. The buck stops at the top.