There are pirates of all different kinds all over the world, and still exist today. The pirates that Disney portray in its entertainment are the Pirates of the Caribbean circa early 1700s. While there are many reasons they came about, some of the leaders/captains of those pirates were acting as privateers and paid by the Crown to antagonize the Spanish. There was also an large element of them that were trying to organize a rebellion to the Hanoverians that took the throne in the early 1700s, and they were doing so out of a sense of patriotism to the old line rule in England.
Of course there were some bad apples, thieves, murderers, rapists, etc., as there are in all civilizations, but they were not all that way. And yes, it was a brutal time. That was just a reality of that time period in history. Life was not as comfortable as we have it now.
There was a code they generally followed. In fact, the Pirates of the Caribbean operated like a republic and the seat of their power was Nassau. They actually did treat everyone equally for the most part and black and white people, served together as a crew. Some of the pirate ships attacked slave trading ships and freed slaves held on board and took the money/treasure aboard.
So for the pirates we are talking about that are subject of the Disney pirates, I would hardly equate them to ISIS. Not even close.