Piracy Based Economy speaks to an economy where the basic means of performing a transaction is piracy. Every trader is, therefore, a pirate, and everyone who is economically active is a trader, and therefore again, a pirate. In this economy, piracy is not a bad thing, it's simply the way things are done.
The piracy would probably be a means of negotiation or barter, except that instead of setting prices and haggling, one party attacks the other. Since trading invariably involves an exchange of goods, and since everyone is a pirate, trading in a piracy based economy involves two pirates performing piracy on one another at the same time. Its just the way things are done. A good deal is when you pirate more than you lose, or pirate what you want or need while suffering losses that are smaller, or on goods you do not want or need.
The act of piracy is also less deadly and destructive than we would imagine, just in the same way that the cost of trading (interest, fees, taxes, cost of business) cannot exceed certain thresholds otherwise one or more parties will cease trading, piracy by all as a means of living implies that it is sustainable.
Finally, pirates cannot just pillage (trade), someone somewhere needs to produce. In the same way that traders cannot exist without having an excess of goods to trade, piracy cannot exist if it is the basis of an economy without having an excess of goods to survive pillaging and to pillage.
Imagine the world is a set of islands, and some islands have kinds of food and fruit growing naturally, and others have others. No beings can survive on one type of food only, and since piracy is the default means of trade, strategies evolve to take. For example, two smaller islands get together to raid the island of a third. A larger island becomes weaker when it is away on raids, allowing a smaller force to get away with some theft. Smaller forces band together to pillage larger forces and larger forces split to attack multiple smaller forces. Co-operating forces will pillage from one another while co-operating and larger forces may do the same on their own forces as they return with goods pillages from others.
The native Americans were pirates. The native Africans were pirates. The native Asians were pirates. All ancient people, before the advent and understanding of money and trading, were pirates. Colonial forces pirated from one another, just as less developed forces pirated from one another and from colonial forces.
Recognizing only major European and Colonial powers as pirates is a major accomplishment, being that it is narcissistic, bigotted and racist - all at the same time! There was ever only one noble savage, and it was us.