"Kill me" is very often blamed on the traders, but usually I place the blame on the pirate. Over-taxing is the problem. If my trader is flying a fully loaded Whale I can pay 2 million - because I'll still get half my profit when I deliver my goods (on my standard route). I've been ransomed for 2 million in 500 cargo ships. I've been ransomed for 2 million when having no cargo. I've been ransomed for "all your cargo" which means not only 100% of my profit gone - but also the purchase price! It makes no sense at all. I prefer to say "Destroy the ship. The insurance company will give me a new one when my pod reaches safe harbor" over "Kill me" but it's the same thing really.
My pirate char's demands are a LOT lower than any pirates my trader has ever been caught by. I'm still having fun, but more importantly - the trader gets his fun too, and makes a profit, and I can catch him on his next run too. Heck, he probably won't even run because he knows the demand is resonable.
Personaly I feel overly high demands are one of the following:
a) a result of ignorance
b) plain greed
c) a bad excuse to make the trader say "no", so they can kill you and feel like big men
Stop the overtaxing, and you stop 90% of the "kill me" comments. Simple.