Black Sails is literally about a gay man trying to overthrow England after he was exiled for being in a relationship with another man. That’s not subtext, that’s the text. That’s the plot, explicitly and specifically. 

Black Sails has three major themes: Narrative, shame, and monsters. These are all set up from episode 1. And how these themes play out hinge around the main character being gay. His own internalized shame, the way England has worked to turn him into a monster to their civilization, the stories that get told and the ones that don’t. 

People who are like “he just happens to be gay, the story isn’t ABOUT that” are missing the point entirely. It would be a fundamentally different show if he was straight. Him being gay is ESSENTIAL to the show, both in terms of plot and in terms of message.