In terms of the title of Pirate King instead of Pirate Queen, there are two main explanations:

• The role of the Queen usually, in a patriarchal society, is to keep track of and maintain the treasury. This task was seen as menial to the King, as he was too busy going on conquests and stacking glory and honor to his name. This is not to say that Queens do not have influence or power, but I feel like a King carries more power and weight compared to a Queen due to gender expectations. Plus the title King usually doesn’t need the accompaniment of Queen to strengthen their influence. A King can be by themselves. And Pirate Quinn is the ultimate King in her own right.
• Try saying Pirate Queen Quinn five times – fast.