Golden age pirates were generally fairly rational economic actors, they wanted to terrorise you into a quick surrender and potentially recruit from the defeated merchant crew. Once you'd surrendered they usually had little need for theatrics like walking the plank, while there absolutely were brutes who'd dish out violence for the fun of it this wasn't the favoured outcome generally because it's expensive to the pirates. It's why the pirate flag is so important, just possessing one is enough to hang you so it's a reliable way of saying 'we're outside the ordinary rules of engagement, do you really want this fight?'

Of course, if you fight they might quite instrumentally make an example of you to enhance their reputation, and increase the chance of future surrenders. If every pirate captain did that to every ship though, he wouldn't be in business long.