Contrary to encryption you don't need guns to safely communicate over the Internet, say with your bank. So I'd argue that strong encryption is a lot more important than guns.
Police violence is more of a way to discourage wrongdoing on the part of rational actors. Irrational actors (terrorists, mentally ill, drug-addled, enraged, desperate) probably won't be affected short of an oppressive police state.
If you buy that argument you could also argue that govermnets should be trusted as a holder of cryptogrphic keys.
Probably wouldn't end well for you though.