Earlier quoted context omitted.
The "sensible gun regulation" isn't, that's the thing. Indeed, the people calling for it are so proud of being so ignorant about guns and gun laws that they often can't even accurately say what class of guns they want banned, they've coined a term - "gunsplaining" - to mock those who point out when they don't know what they're talking about. Features of the current US pro-gun-control movement include the notion that…
I don't think this is a terribly good counterargument, personally. To me, the gun control movement is basically reacting to several high profile mass shooting cases. Your argument to me seems to be the equivalent of countering, say, a mother who lost a child to a drunk driver, with an argument that they shouldn't be concerned, because they don't know about the technical details of engine displacement or the neurophar…
What if gun owners who didn't keep their guns locked in gun safes had their bullets replaced with rubber ones, or had mandatory trigger locks installed on their guns?
I dunno, I'm just spitballing here, but cars are heavily regulated, licensed, the whole nine yards, and if we had a tenth of that applied to guns, we could probably do a lot to reduce gun deaths and gun violence across the country.