It's been pointed out before that as pirates didn't fight or steal from each other, this isn't actually a 'pirate' game. Our characters may dress like pirates and it appears to be set in the Caribbean during the age of piracy, but technically it's just a PVP skirmish game with some snakes and sea shanties thrown in for good measure. I've actually been thinking (perhaps over-thinking) that SoT is very much like the Milgram experiment in the 1960s.
The 'Milgram experiment on obedience to authority figures' was a series of social psychology experiments conducted by Yale University psychologist Stanley Milgram. They measured the willingness of study participants, men from a diverse range of occupations with varying levels of education, to obey an authority figure who instructed them to perform acts conflicting with their personal conscience. Participants were led to believe that they were assisting an unrelated experiment, in which they had to administer electric shocks to a "learner." These fake electric shocks gradually increased to levels that would have been fatal had they been real. - Wikipedia
In other words, will someone inflict misery on another person simply because they're told they can, and if so, how far will they go?
Sea of Thieves gives players two main game styles to play by - Passive or Aggressive. We are told that we can 'make our own fun' and play how we want to. If we want to chase pigs and dig up chests, we can do that. If we want to steal pigs and chests from other players and then sink their ships, we can do that too, but in doing so we disrupt their fun for our own entertainment. In effect, we are 'overriding' their chosen game style with ours and then telling them they're not playing it right when they complain, when in reality, both game styles are perfectly valid, or at least they were intended to be. The devs had expected us to work together on skull forts for example. I don't think they ever imagined three or four galleons would fight each other for hours until only one retained the will to continue.
They have given us a choice to work with each other or kill each other, to employ subterfuge and in many cases to literally shoot each other in the back and it seems (from my experience) that most players choose the latter style of gaming. So in essence, we're told that "Yes, you can kill that guy and steal his loot but you don't have to -it would 'ruin' his game" and apparently most of us think "Great. Let's do that!" We know that when the guy in the sloop heads away from us when he sees us that he doesn't want to fight, but still we pursue him for an hour to the edge of the map and back, we launch a volley of cannon balls at his ship and while he's busy repairing down below, we jump aboard, shoot him in the back, take the one castaway chest he had then steer his sloop towards some rocks.
If you look at it the way I do, one could consider the basis of this game to be a psychological experiment to see how many of us, when given the choice, would be good or bad where our decisions affect real people and not just NPCs. Yes, I know it's still a game, but it's one that allows and perhaps even encourages the act of distressing other players for entertainment.
