The NAP is a fiction made up by American libertarians. It is not a doctrine adhered to by the Russian navy.
The reality of the matter is that any vessel not flying a real flag enjoys no standing whatsoever in the laws or treaties of the seas. Freedom of navigation is a right of states, not individuals. If you are not a state or under the protection of a state (a real one, not a comic book one) then you do not have the right to navigate the high seas.
Which is why so many ships sail under the flags of states with the ability to protect them, like the USA, Great Britain, Russia or China, and not Panama, Liberia or Bolivia.
If you sink a ship registered in Panama, you have made war against Panama and transitively against the United States of America and all other signatories of the Inter-American Treaty of Reciprocal Assistance.
If say Russia sinks a Bolivian boat, there are plenty of other major nations with navies that will get upset about it just because they want to keep the Russians in check. Not because they care about Bolivia. If the Russian navy sinks some stateless seasteading anarchists, nobody is going to give a crap.
> The NAP is a fiction made up by American libertarians.
That's true, but that's also true for any other human doctrine, from human rights to US constitution, so I don't see how it makes it any less important.
> It is not a doctrine adhered to by the Russian navy.
The reality of the matter is that any vessel not flying a real flag enjoys no standing whatsoever in the laws or treaties of the seas. Freedom of navigation is a right of states, not individuals. If you are not a state or under the protection of a state (a real one, not a comic book one) then you do not have the right to navigate the high seas.