According to the Miller court, it protects library books. That implies a protection of libraries. Let's not get juvenile, here.
"Try this one; "A well-educated electorate being necessary to a secure state, the right of the people to keep and read books shall not be infringed".
I'd rather not. It's not an accurate analogy. The second amendment does NOT read, "A well-trained populace being necessary to a secure state, the right of the people to keep and bear arms shall not be infringed".
The second amendment refers to an institution, a well regulated Militia, not simply people with guns.
And you are also willing to claim that "libraries" are an institution. Your claim is equivalent to mandating that only government can open or run a library. It's nonsense.