Sometimes the reasoning is specious and a fig leaf (e.g., Heller); have no idea how good it is here.
The decision, as written by the late Scalia, to create an individual right bears no resemblance to any historical or legal precedent. Acting as amateur linguist and etymologist, it is ironic that Scalia, a so-called Originalist, also ignores the original meaning of the terms in the amendment.
This is independent of whether 2A is currently useful, or—even more importantly—whether it was even a good/effective idea in the first place.
People should read the decision. People should also read the dissent. They should also read commentary on the decision. They should also read the legal and cultural history of 2A.
There's no bad faith in thinking Scalia et al got it wrong.
That's a common feature of Supreme Court decisions, and I find many Supreme Court decisions to be very interesting reading, including those from past decades.