I have no doubt that Luther and others feared this may happen. Luther and others simply stood by the truth wherever that was bound to take him. I don’t think Luther was too concerned about this even though he must have realized it could happen.
Much of this was taking place during the Renaissances where there was great emphasis on knowledge and learning. I’m sorry the author doesn’t speak to this more. The Renaissance by this time had been going on for almost 300 years. It was a time when great emphasis was placed upon learning and knowledge. This, no doubt was probably also one of the reason Luther’s father scraped together what little he had and sent Luther off to school. While the rest of society was experiencing this, including the hierarchy of the Church, the masses in the Church were not.
The reactions of the Puritans (and other Protestants) most likely were an overreaction to the environment they found themselves free of. Regrettably, Protestant laws (e.g. burning heretics) were established somewhat like the Catholic Church since that was the only basis the early Protestant had to compare against. It became a tit-for-tat. This is not to condone Protestants action, simply to state some of them might have been somewhat like the Corinthians in taking their liberations too far.
BTW-I like your picture.