That last suggestion is probably taking the analogy a bit too far.
Why? As a kid, I had access to long guns
& handguns without restriction.
And we had no wrongful shootings at all.
If the criterion of someone not being harmed
justifies smoking, then it can be applied to
drunk driving & careless gun storage.
It's not necessarily anecdotal, since there might very well be circumstances or other identifiable factors which make it less risky for some people than it is for others. In some cases, it might be genetics, if some people are able to sustain more damage to their bodies than others.
Those factors would apply to smoking & lax gun storage too.
For example, gun storage safety is less necessary when no one
suffers from depression, which could be strongly linked to genes.
As for those who drive drunk, I guess some might be able to hold their liquor better than others. I remember an inventive defense used by airline pilots who were charged with heavy drinking prior to a flight. They said that they were such raging alcoholics that their tolerance was so high that it didn't really affect their flying abilities.
However, you wouldn't want to leave handguns out for the kids, unless there are some extraordinary and extreme circumstances, such as a zombie apocalypse.
So leave the cigarettes & booze out for the kids, but not the guns....what's the difference, so long as some aren't harmed?