If that's the attitude I will just blow them up and take whatever is left
That's not how Elite works... if you blow them up there will be nothing left for you to take.
It is not like EVE where destroying a ship will allow you to loot whatever modules, ammo and equipment survived the explosion.
The ONLY way for you to get ANY loot from someone as a pirate is by forcing them to drop cargo.
If you decide to simply destroy them then the only things you achieve are;
1) Increasing the bounty on your own head which in effect means painting an even bigger target on your own back when being scanned by bounty hunters.
2) Wasting credits on ammunition. And I say waste since you get no loot or profit when destroying a ship.
3) Putting yourself at risk since opening fire and engaging in a fight might get your ship damaged or destroyed, depending on how good the other guy is at fighting, how close his friends are, how many security ships are in the area (and they WILL assist someone with Clean crime status if you attack them)
The fact that destroying a ship leaves NO loot makes piracy much more challenging than in games like EVE. In EVE you never really ransom anyone, you simply warp scramble them and destroy them, then take whatever is left. In EVE the piracy is about looting the wrecks and bragging about the kill-mails.
I am very happy that Elite has chosen a different approach to piracy, and the way it works in Elite is much better.
Now you have to threaten the target to drop their loot, or prove that you mean business by damaging their ship and threaten to destroy them.
Another thing to keep in mind is that shooting a Clean target gives you a small increase on your bounty, but actually destroying them counts as a murder and places a much higher bounty on your back. So you don't really want to kill your targets as a pirate.
And if you are just killing them, then you are not really a pirate but a murderer (some might even call it griefer)
TL;dr
Destroying ships means all their cargo is destroyed and you get NOTHING as a pirate. So the statement: "I will just blow them up and take whatever is left" does not work in Elite.