The NRA has higher approval than him because his (and the “progressives”‘) views are out of the mainstream.
[Update a few minutes later]
We notice two things these three men have in common. First, there is no indication any of them have ever misused a gun, either accidentally or deliberately–in contrast to Marshall’s correspondent, who nonetheless evinces a smug sense of his own superiority over them.
Second, they all have eccentric political views, which Marshall’s correspondent seems to think is an argument for taking away their guns. Never mind the Second Amendment, do these guys even respect the First?
Not really. They just pay lip service.