FD sold the game on the premise of being a pirate or a smuggler and didn't even bother to list trader on their sale page
Shooting the same npcs around the same asteroids might be fun for some people but for others we want the player interaction that was promised to us.
I pirate because it's fun, you have all sorts of crazy encounters and meet people for good or for bad. I traded for like 400 hours and was only pirated a few times but each time was a good experience mainly because I knew when to run and when to fight.
FD need to work on the game mechanics for piracy for both traders and pirates but even if they are a bit broken (combat logging, interdiction cooldown, high wake jumps, broken black market system) I'm still going to pirate and I'm still going to kill traders that don't comply to my demands.
I killed two T9 players last night filled with palladium, one thought he could run and then when his drives were shot out though that silent running would save him and when it didn't he self destructed. The other thought they could use mines and by the time they stopped I had a malfunctioning burst laser through heat damage from shooting him that it ended up stripping the last 5% of his hull before I could put my weapons away. The next time I interdicted him he stopped straight away. Do I feel bad? No. I used to trade myself and if I was in a T9 I wouldn't risk death for a few t of palladium that I could make back profit wise in another run.
The game is all about risk. You can run if you think 20t of palladium is too much to drop for a pirate vs your rebuy on a T9 and full hold of cargo but you can't complain about it after the fact as it's part of the game. If you want to play open without being pirated you don't use thrudds or slopeys and you find your own trade data on systems outside the main systems and grind away in peace or you go to solo or group. Atleast most player pirates message you with demands before shooting.