Here's a couple others:
38 CFR 38.630 - Headstones and markers. - "VA will furnish, when requested, a memorial headstone or marker to commemorate an eligible individual whose remains are unavailable." - https://www.law.cornell.edu/cfr/text/38/38.630
Who is threatened with violence for breaking that law? At most, a VA employee can be fired, yes?
36 U.S. Code § 106 - Constitution Day and Citizenship Day - https://www.law.cornell.edu/uscode/text/36/106
That's another completely voluntary law ("are urged"), and the Supreme Court didn't get involved.
There is no implicit argument that additional forms of authority are necessary.
In other words, never assume someone is implying something else when making an entirely different argument.