Survival mom has an excellent piece called 10 Myths About ‘Preppers’.
I find the myth that has the most currency among people I meet to be that Preppers are extremists ad her refutation of that myth is right on point:
As I said above, there are extremists in every group or social gathering all over the world. These people define the far reaches of what is acceptable and the majority of us hang out somewhere in the middle.
Speaking for myself, the only thing I am extreme about is trying to learn how my grandparents did things and how they got by. They were more self-reliant and that is my “extreme” goal. I do not want to have to rely on the grocery store as much, or worry if my city drinking water is actually safe to drink.