Well, the flip side is that we on the pro-gun side can make a solid case that guns also aid those who others try to rape, assault or even kill (but of course not defraud) by, for example, providing an equalizer to the physically weaker. E.g. I couldn't help but notice that the members of the mandatory class for my state's concealed carry permit where strongly weighted towards the older.
Encryption backdoors at best do nothing to help against private actors wishing physical harm on people, and the death toll of those killed by governments and government aided private actors (for the US, include KKK types including or aided by local law enforcement) suggests we don't want to give this sort of power to governments.