I think I agree that in current times it doesn’t seem particularly fair. But there was apparently a reason…
It seems the constitutional question hasn’t had an opportunity to legally be asked. Unfortunately/Fortunately, Seaman’s Manslaughter is a historically uncommon charge. As pointed out here, “During its first 142 years, there were roughly eight major prosecutions, spanning 1848 through 1990.” Certainly it has come up more in recent years.
Perhaps the closest the courts have come to clarifying the differences between Seaman’s Manslaughter and Common Law manslaughter was United States v O’Keefe in 2005. O’Keefe appealed to the 5th Circuit Court after the District court rejected his argument that the jury should be instructed that the government must prove Gross Negligence. Both courts disagreed.
Importantly the District Court stated:
“In light of the unique dangers of maritime travel [and] the vulnerability of passengers on board such vessels …, it was reasonable to impose on such crews a heightened degree of care with the parallel lower threshold for criminal liability.”
And a Circuit Court footnote:
[Section] 1112 and § 1115 are separate crimes addressing different concerns with different penalties. Involuntary manslaughter as defined in § 1112 applies to all persons, regardless of where the offense occurs or whether the offender had any unique responsibility or fiduciary duty towards the victim of the crime. On the other hand, § 1115 applies only to commercial vessels whose operators and owners, historically speaking, “daily have the lives of thousand of helpless humans beings in their keeping.”
Further text from the ruling interpreting Congress’ intent:
The district court, after conducting a historical analysis of how other courts have applied § 1115, concluded that Congress did not intend that proof of negligence or heat of passion would be required for a conviction under § 1115. The court cited at least five early cases, all strongly suggesting that Congress did not intend a requirement of the heightened mens rea that O’Keefe seeks.
the district court stated, “[i]t appears clear from the purpose of the statute, its legislative history and the available case law interpreting it that any degree of negligence is sufficient to meet the culpability threshold.”
We reject O’Keefe’s contention that Congress is presumed to have incorporated common law meanings of negligence utilized under § 1112 in the terms used in § 1115, for the same reasons given by the district court:The Court does not agree that because the predecessor to § 1115 was called manslaughter that it automatically engrafts the case law interpreting other definitions of manslaughter from other statutes.
Another recent prospect for raising the constitutional question would have been the Deepwater Horizon case of United States v Kaluza. It had a high enough profile and big enough players that the appeal and question might have arisen had the same 5th Circuit court not ruled Kaluza, based on the position he held, couldn’t be tried under Seaman’s Manslaughter. So it was moot.
But to the point of why are seamen treated differently. The closest parallel job by the courts description I can think of is commercial airline pilots. But there’s no Airman’s Manslaughter is there?