It doesn’t really matter if it’s petty or not, that stuff is subjective, he hurt you, that’s a big deal, the healthy respond is always to cut off communication and not give any more time to them but you wanted a badass breakup fair play you got it and you can tell it made him feel bad and lash out by dismissing it as petty and dumb instead of acknowledging the part he played, bullet dodged, good luck with the next one