The other place where Scalia screwed the pooch was with the fuzzy language abut "presumptively" lawful restrictions [which is to say, "infringements"] on the RKBA. What this really meant was "There are a lot of gun regulations around the country that are not part of this case, so we're not going to address them today. Until challenged in court, we'll presume that they're okay."
That is actually one of the important arts of Scalia's decision. One problem with Second Amendment litigation is that for every Otis McDonald, there are 100 guys who should be in prison claiming the Second Amendment protects them. The language you quote gave the lower courts an easy out to dismiss those bad cases without doing any real legal analysis.