I’m not sure I ever really thought through what a weird position Laertes is in in regards to Hamlet. He has to fight him but also has to retain a certain amount of deference. He can’t get into this duel with Hamlet and start doing the dozens. He can’t shit talk him. He can’t REALLY challenge him. He can swing his sword at him because that is the prescribed task here – but otherwise, his hands are tied fairly tightly. No wonder he’s happy to sharpen and poison a sword to stick into him.