Most big transports got nerfed. The patch notes didn't reflect these (among others) changes for some reasons.
Most traders that get pirated are new people it seems that know not what Rp is, nor do they know basic math.
They just don't want to give the pirate the satisfaction it seems. Maybe they even see them as griefers or something along that line.
Personally I enjoy some well done piracy on my transports.
For new people who read this. Even if you get taxed 20mil with a cargo hold full of ore... It is still better to pay. Piracy won't get encouraged so much to invoke another golden age and you don't kick your cr/sec into the negatives.
Edit: some autocorrect fixes. Also ninja... Phone writing takes long.