Some people will sacrifice a great deal to preserve a myth, even their lives. These two points are a given. Now the issue is, what is point 3. You must have some objective criteria for determining fact from myth. There are stupid people in this world.
Some stupid people send e-mail.
Ed sends e-mail, therefore he must be stupid. This is irrational. I need objective criteria for determining who is stupid and who is not stupid or else it is merely my subjective opinion. The same is true for determining fact from myth. Historicity is beside the point.