Yes, the Supreme Court role is to determine the constitutional issues of cases brought before it. In that case he refers to, someone was challenging the constitutionality of a District of Columbia law requiring handguns be dismantled and basically rendered inoperable inside the home. The appellant was asking the Court to render a decision based on the 2nd amendment. That they determined D.C.'s restrictions violated the constitution in no way endorses or interprets the Second Amendment in any general sense.Isn't it the Supreme Courts job to INTERPRET the constitution, not to try to CHANGE it? They are supposed to be more like a referee in a game, they are to tell when someone oversteps the rules and steps out of bounds, not MAKE the rules. There personal opinions of whether they like or dislike it are irreverent, the ruling is to be whether it abides by the constitution, not to give his opinion on why the constitution should be changed.
He is no longer on the bench, so he is entitled to state his personal opinion. It is neither irreverent or irrelevant, any more than yours or mine.