People don't take a 256-bit cryptoalgorithm into a middle school and kill kids with it, so I don't think the analogy works exactly. Maybe if you print it out on paper, or use a floppy disk or CD, you could cut a few people.
Edit: Devil's advocate.
I just think that a politician moved by the desire to do something could construe non-backdoored encryption as something that "helps the enemy."
:-/
They occupy exactly opposite quadrants on the useful/dangerous axis.
There is a cost to having a society saturated with firearms. The vivid, individualistic, but rarely used benefit of personal defence has to be weighed against the boring, common case of excessive violence and escalation due to access to and glamorization of firearms.