The report says that’s because they could not find evidence to attribute the charge to any person, and figureheads cannot be imprisoned just for a crime of their company in the primitive laws of this very small island country in the Caribbean, since nothing like this has happened in that country before, apparently. The report is sort of “exploiting” the existing rule that corporations may be accused as perpetrators to accommodate for the punishment of this crime to actually be able to convict and punish; the charge of “corporate manslaughter” has never happened before either. c.f. https://hfpsc.org/corporate-homicide-manslaughter/