Self Defense vs Recreation
Based on a cursory reading of the State's position they still view the RKBA as a permission, not a RIGHT, and only for recreational purposes. This is why MD "allows" transportion an unloaded firearms, locked & secured in one's vehicle, to places like gunshops & ranges. This has NOTHING to do with Self Defense.
Let us remember, in both Heller & McDonald, that the Supreme Court ruled that citizens have the RIGHT to keep & bear arms for Self Defense. As has been noted above that this right is most crucial in the home, but nowhere did the Supreme Court limit Self Defense to in the home. So MD's position, as well as many other states & DC, is that one may keep & bear arms in the home but they many NOT use them for Self Defense - even in the home. They may keep arms for recreation but NOT for Self Defense. This is in complete discord with the rulings in Heller and McDonald.
This is where I believe the issue truly lies: the RIGHT to Self Defense. It is based on a RIGHT to life and the RIGHT to defend that life. By denying citizens a RIGHT to Self Defense anywhere is denial of their unquestionable RIGHT to life. Self Defense is a Natural Right. IMHO this is what the 2nd Amendment was designed to protect as ruled by the Supreme Court. Twice.