The Hamlet Project

Fuck yeah, Laertes! You tell him!
This is probably why Shakespeare made the priest such a dick so that we’d be on Laertes’ side to read the priest the riot act. And getting Laertes riled up by this churlish priest is useful because it means when Hamlet reveals himself in a minute, in a pretty churlish/dickish way himself, Laertes will be amped up and already furious.
Shakespeare doesn’t need the priest to be a dick for Laertes to mention his sister – he could just as easily say something like “Lay my sister in the earth” but he does need to get Laertes good and furious so he and Hamlet can have a dramatic grapple in a grave.