“This means you are not doing Scrum. What you are doing is Cargo Cult Scrum.”

No, maybe you are doing what makes sense — which might not be Scrum.

A-lot of what happens in a sprint 0 is not development — it is research — and research is not something that Scrum was intended for. During a sprint 0, people are thinking through how things will work — developing an “architecture runway” as some say. They are also setting up tooling, which often involves a-lot of new tasks for people. Trying to force it into a sprint format is counterproductive, IMO.