It was not an act of piracy, despite the outcry...
No, it does matter what country did it. More specifically, it depends on whether a country did it. Because if any country's armed forces did it, it is not an act of piracy, by international legal definition.
As David Bernstein pointed out at Volokh Conspiracy, "
As another maritime law/international law observer pointed out:
A look at UNCLOS, international law of the sea, appears to support that distinction: