No one thought Joan of Arc was a “nut.” A heretic, yes, because she reverted to male clothing was the reason given for her execution. In fact, the Burgundians who prosecuted her were amazed at her brilliance. Some of them deeply regretted her judicial murder.
Perhaps the word ‘nuts’ would not fit the conventional thought of the time. Certainly, highly inappropriate and unthinkable would apply for the customs of 15th century Europe. She frightened a lot of people with her fearless faith, and as you say, history tells us much regret and reconsideration ensued in the many years since. That was my original point. I have always found her very fascinating and inspirational.