Karen, I think you are completing missing the point of of what dunning is.
The techniques described above try get an already paying customer back in good financial standing. The customer has already decided they want the service by signing up. Dunning is simply trying to get them to pay their bill. A customer canceling is completely outside the scope of this. In that event they are let go.
In Joelle’s first pointer “Stop Pre-Dunning. Turn it Off. Now.” she is telling us to stop sending pre-dunning emails. A pre-dunning email would be sent when you detect that a card might fail or has expired. This is very different from an upcoming charge email. Those should absolutely be sent and I’d expect that Joelle would agree.
From a customer perspective what if you were using a phenomenal service and one day it stopped working for you. You log in and find your account has been canceled. Why? Because you got a new credit card and didn’t inform the service. These dunning techniques are precisely designed to prevent this situation! In no way do they trap a customer. If the customer wants out they can cancel or just do nothing.
To call these techniques as gross is just a complete misunderstanding of how online business can use modern technology for for the age old problem of recovering accounts receivable. See https://en.wikipedia.org/wiki/Dunning_(process)