@RamistaR:
Do not forget that the word pirate can take different meaning in One Piece.
Sea people chased by the WG's marines.
For all we know they were branded as pirates and given bounty only because they did not want to join the World Government.
I doubt he got such bounty and money from simply playing nice.
Maybe the Navy's treasure was stolen from all the pirates that tried to attack their country. I hardly see the Happo Navy steal from innocents.
I don't know why you would believe so. They were pirates. Luffy has a weird way of doing it but everyone else has been going the good old fashion violent way especially the old generation. Plus he seemed to think Blackbeard was the one who knew how to do stuff.
But when Garp defeated the fleet they lost their commander and their treasure. So they had no choice but to join the World Government. Well that's just a theory of course.
You are talking about the navy or the country? The treasure was personal to Chinjao & his clan/family. And they seem to have simply become part of the country rather than the world government itself.
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@RamistaR:
I think Wapol is invited even though is country was just created. Mind you he might be a special case because he is completely sold to the WG.
He did invented Wapometal that helped in the war.