Now it seems to me that, read as broadly as it is written, the statute violates the First Amendment. Cases such as NAACP v. Claiborne Hardware Co. (1982) make clear that speech intended to retaliate against people, and even harm them economically (and risk leading to violent attack against them), is constitutionally protected: There, it was speech by black activists retaliating against black citizens who refused to boycott white-owned businesses, but for First Amendment purposes retaliation for lawful (indeed, constitutionally protected) purchasing behavior can’t be different from retaliation for passing information to the police.

The District Court had rejected the First Amendment argument, concluding that the statute is constitutional because “criminalizes speech only upon proof that the defendant intended to retaliate against a witness”; but I think that can’t be right—an intent to retaliate doesn’t strip otherwise constitutionally protected speech (again, speech that need not fall within any First Amendment exception, such as for true threats or for incitement) of constitutional protection.