Why are pirates called pirates? Because they just arrrr. It’s an old joke but, hopefully, a good one. Speaking of old jokes, some have accused Ubisoft of stretching the Assassin’s Creed franchise well past its elastic limit, claiming that its storyline of virtual reality, crackpot historical conspiracies and rival secret societies has become too convoluted to offer any enjoyment. It’s an argument that, in a medium dominated by annual rehashes of FIFA and Call Of Duty, does not hold much water and, to happily mix that metaphor, is blown out of the water byBlack Flag. As with previous outings, we are once again given access to…