I made a very long post where I tried to trace how the romanticization of pirates and a lot of the tropes popularly associated with them actually have roots in contemporary 17th and 18th century literature about pirates. It's a bit long and rambling but here it is: How accurate is the stereotypical depiction of a pirate?

You can also check out this post about contemporary pirate songs which further shows some of the ways that pirates could be romanticized even at the time: Are any actual songs from the Golden Age of Piracy known today?

Here are three other posts that discuss some common pirate tropes:

Did pirates ever bury treasure or use cave hideouts?

Did pirates really make people walk the plank or leave them on deserted islands?

Were there actually birds on ships in the 19th century, or is the pirate with a parrot on his shoulder entirely a Disney invention?

Lastly, for some examples of how pirates really were nasty violent criminals you can check out these posts: I am a sailor on a british trading ship in the golden age of piracy. I get attacked by pirate. What do I do?

People say that Pirates would "rape and pillage", but how much rape did they actually commit? If I was on a ship crossing the Atlantic in those days, should I, as a woman, need to worry about my virtue in the event of a Pirate raid?