Robin Vander Wall
It’s a legal standard that becomes important to the manner in which a case is disposed of. The attorney(s) in this case apparently decided that the case would be strengthened by avoiding an outright assault on the constitutionality of the statutes themselves (what’s called a facial challenge) and preferred for the Court to address the constitutionality of the registry statutes as they apply to the plaintiffs named in the suit. Because this was the posture of the complaint, it’s not appropriate for the Court to provide relief that the plaintiffs never sought.
Here’s a bit of Wiki about the distinction between facial challenges and as-applied challenges:
In U.S. constitutional law, a facial challenge is a challenge to a statute in which the plaintiff alleges that the legislation is always unconstitutional, and therefore void. It is contrasted with an as-applied challenge, which alleges that a particular application of a statute is unconstitutional.
If a facial challenge is successful, a court will declare the statute in question facially invalid, which has the effect of striking it down entirely. This contrasts with a successful as-applied challenge, which will result in a court narrowing the circumstances in which the statute may constitutionally be applied without striking it down. In some cases—e.g., Gonzales v. Carhart or Crawford v. Marion County Election Board, a facial challenge has been rejected with either the court or concurring Justices intimating that the upheld statute might be vulnerable to an as-applied challenge.