Honestly this is becoming far too emotional for people here.
The reason you couldn't do a "safe" server would be the progression, without the conflict this game would become a museum, players sailing around taking in the scenery with no purpose.
Look at it like this, everything has a risk / reward decision. You can't have risk without reward because you feel that you get nothing for overcoming adversary leading to a quick stagnation of gameplay and killing the experience.
On the other hand you can't have reward without risk as you gain no value to your possessions. Your endless gold all comes from dull grinding. It gets too rinse and repeat.
The problem comes when trying to make a balance, especially in open sandbox worlds. You need to be able to force interaction at the right frequency without overdoing it. RARE wanted to do this with hope that we would all meet during our voyages but this ends with two current outcomes either we are over engaged and cry out for a safe haven OR we are left alone and get bored,turning to aggressive interaction with everyone so we can get some excitement.
NPC ships could solve this however RARE have repeatedly said this will not be in game. (this is somewhat conflicting as merchant ships were hinted at one point but then told all sails you see are other players, confusing i know.).
A safe port then, this renders the potential of having campers sit outside it awaiting your approach or even just ramming you or boarding you to steal what's on board, all easily achieved if you cannot fight in the standard sence.
Another outcome as means of deterrence is fort defence at outposts, these would be neutral until aggressive actions take place and would then turn hostile. This again could be abused in the same way, people taking the killing shot just before sale knowing they can cash in before they're killed themselves.
So that leaves deterrence via reduced or closed vendors, so you can kill the carrier but your reward is less for the doing so or is locked off at this outpost, you would just sail to the next and cash in there. This also does nothing to those spawn killing just for fun so really doesn't achieve anything.
All of this is hindering to the tag be more pirate and more importantly comes down to one real issue, while in beta we all know that the progress will be reset so why try to reach the best faction respect its all for naught, that thought turns people into the lets kill for fun lot your all concerned about.
My last point still stands aswell, if people want to sit at an outpost and wait countless hours for a new spawn to kill, are they really going to be enjoying the game?