I don't hold with any of this "codified right" nonsense.Forgive me, but the tone of this comes across like talking to someone from the sovereign citizen movement. Maybe you don't think workers have the right to a safe workplace, but the majority of US society does and has passed laws to ensure it. People don't believe in workers rights because there are laws; there are laws because people believe in workers rights.
It's worth discussing if you think the law is wrong, but outright dismissing it as if it doesn't exist is a strange take. I hope for your sake you aren't a supervisor.
So if I understand your position, it's that workers should not be guaranteed a safe workplace. You point out deaths, but overlook the other non-lethal incidents. So assume their bad practices lead to a criticality event that subjected other employees to radiation exposure. Employees that had no input into the decision or actions that lead to the risk. Is that ok in your opinion as long as the number of workplace injuries is below a threshold? Is your stance that the employer can just hand wave away any responsibility by essentially telling the employee "Welp, at least you're not working in a steel mill." By contrast, worker safety regulations define workers safety in this case on a radiation dose basis, irrespective of what goes on in a steel mill. I would say that's a much more objective measure of managing worker risk.
The main point I'm making is that your comparison to the aggregate average workplace injury rate is the wrong perspective. The way organizations like OSHA look at employers is by comparing similar industries. So the safety record of a chemical processing plant isn't compared to something like a pharmacy because the nature of the risks are different. The article clearly states that LANL has a much worse safety record to comparable facilities. I agree that safety regulations can go too far, but you're selecting the wrong benchmark and using it to justify erosion away employee rights with a fairly subjective and arbitrary definition of what is determined reasonable risk.