Not sure what you mean in this context about "open-carriers", "open carry" is the oldest and historically least restricted form of carrying weapons, vs. concealed which prior to the Civil War the first restrictions were imposed upon under a questionable theory that would discourage dueling.
You, and if SCOTUSBlog got it right, Roberts and Kavanaugh are also wrong about needing a license, for half the states in the nation have "Constitutional Carry", no licence required.
"As an anti-gun person, this decision is not surprising, but still depressing."
You've got a remedy right there in the Constitution, repeal or even reverse the Second Amendment, or call a constitutional convention and repeal the whole thing which far too many want to do because they find it restrictive.