If you’re a PvP pirate you’re never really risking anything. You’re probably carrying a few hundred cannonballs (5k gold?), some wood and some food. If you are sunk, you get your ship back fully repaired for free and lose only the cannonballs, wood and food. If you sink someone carrying treasure, you get their entire haul and just have to get to any port to sell it.
If you’re a PvE pirate returning from a quest, you don’t really get your quest rewards until you get back to port with your treasure. If you lose to a PvP pirate all that time questing was for nothing. If you fight a PvP focused pirate and win, all you win is some cannonballs, while you have the potential to lose all your treasure, the result of hours of game time.
Having said that, if you’re a PvP focused pirate, you’re going to be bored a lot. The game world is very empty so you’re going to spend a lot of time sailing around, hoping to find someone to grief. If you fly a reaper flag people can see you on the map and steer clear of you. If you’re a PvE focused pirate, it’s easy to find something to do, so you can have a great time sailing around, having adventures… until you run into a PvP player.
The game should really be changed so that PvP focused players have an easier time finding other players to fight. Meanwhile, people doing PvE content should have something significant to gain if they ever beat a PvP player. If they choose to turn and run, there should be safe harbours where they can unload in peace.