Scalia himself acknowledged longstanding restrictions on firearms. "The Court’s opinion should not be taken to cast doubt on longstanding prohibitions on the possession of firearms by felons and the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, or laws imposing conditions and qualifications on the commercial sale of arms." DC v. Heller.
Pretty much every right in the Bill of Rights is subject to limitation, including the First Amendment. Grow up.