I'm not a lawyer, so this is a question, not an opinion...
What's the basis of the judge's decision to dismiss; i.e.,why is the application of the statute limited to commercial vessels?
Being a non lawyer I would think the possibilities are the language of the statute, regulation based on the statute, case law involving the statute, or the judge's untethered (not a legal term...) decision.
It's clearly not the statutory language:
18 U.S. Code § 1115 - Misconduct or neglect of ship officers
Every captain, engineer, pilot, or other person employed on any steamboat or vessel, by whose misconduct, negligence, or inattention to his duties on such vessel the life of any person is destroyed, and every owner, charterer, inspector, or other public officer, through whose fraud, neglect, connivance, misconduct, or violation of law the life of any person is destroyed, shall be fined under this title or imprisoned not more than ten years, or both.
When the owner or charterer of any steamboat or vessel is a corporation, any executive officer of such corporation, for the time being actually charged with the control and management of the operation, equipment, or navigation of such steamboat or vessel, who has knowingly and willfully caused or allowed such fraud, neglect, connivance, misconduct, or violation of law, by which the life of any person is destroyed, shall be fined under this title or imprisoned not more than ten years, or both.
"Any vessel", without subsequent identified exceptions, seems pretty inclusive to me. So what's the basis of the judge's decision?