How can I explain to non-techie friends that "cryptography is good"?

"If lack of encryption allows FBI to catch terrorists, then lack of encryption allows criminals to loot your emails and plunder your bank account."

The rational point here is that technology is morally neutral. Encryption does not work differently depending on whether the attacker is morally right and the defender morally wrong, or vice versa.

It is all fear-driven rhetoric anyway, so don't use logic; talk about what most frightens people, personally. And people fear most for their money.

I would take their argument and replace "cryptography" with "locks and keys on our houses" and see if they still agree:

If more terrorists and criminals would be caught by not having locks and keys on our houses, I would not blame warrantless searches by government and companies in our homes.

Explain it with questions: Do you close the door when you poop? Why? Everybody poops, you aren't doing anything special in there, so what do you have to hide?

If someone leaves a pile of poop downtown in the middle of the road does that mean we must all poop with door open? Simply because the pile of poop was gathered in a bathroom?