I’ve never had a pirate demand my cargo. They always kill me. 
In the past, I’ve attacked explorers in wormholes and demanded that they jettison their cargo. However, alot of the time they’ll waste my time, only eject a part of their cargo, pretend not to understand English, etc.
Now I just kill everyone.
Never give anything to people who shot or scramble you. The loot fairy should decide, and if you will respect her role, she will reward you later.
In my view, this is a very difficult thing to do in EVE. Its just not set up to handle this sort of thing. Hesitation too often means death.
I have posted ideas to establish mechanics to make surrender and ransoms actually viable, but it seems that CCP’s original plan was for destruction more than role play. From the perspective of the tech of the time, I understand. But its 2021 now.
And I suspect a random “necrothread claim” to appear, as if this question somehow lost all its relevance and meaning in 3 months and the pixel count for the text is killing the server. 
Apart from making a pretty explosion , blowing up ships is good for the economy, zkillboard and the lols.
So was hunting whales and beaver, and cutting down trees in places like Iceland and Easter island. And then, one fine day…it wasn’t any more.
Economy is complicated. It simply won’t be boiled down to simple “truisms”.