About the Heller case, it was decided by a 5:4 vote, meaning the majority's interpretation is far from consensus. In fact, Justice Stevens wrote a long dissent, in which he specifically addressed the interpretation of "people". Here is the first paragraph:
The centerpiece of the Court’s textual argument is its insistence that the words “the people” as used in the Second Amendment must have the same meaning, and protect the same class of individuals, as when they are used in the First and Fourth Amendments. According to the Court, in all three provisions—as well as the Constitution’s preamble, section 2 of Article I, and the Tenth Amendment—“the term unambiguously refers to all members of the political community, not an unspecified subset.” Ante, at 6. But the Court itself reads the Second Amendment to protect a “subset” significantly narrowerthan the class of persons protected by the First and Fourth Amendments; when it finally drills down on the substantive meaning of the Second Amendment, the Court limits the protected class to “law-abiding, responsible citizens,” ante, at 63. But the class of persons protected by the First and Fourth Amendments is not so limited; for even felons (and presumably irresponsible citizens as well) may invoke the protections of those constitutional provisions. The Court offers no way to harmonize its conflicting pronouncements.