This Jotaro feels more like a typical shounen protagonist.
He was characterized as "chuunibyou" a little earlier (well, it was a little earlier to me because I've been catching up on the "new" translations, but I think it was a little before he called Avdol "ugly") so I think it's kind of that at work? XD
EDIT: actually, Kakyouin kind of calls him out for it way back in the beginning post #2058458
W-what are you doing, Jotaro!and then use his Stand's finishing move to take the enemy down!Polnareff!That's all the more reason to stop you!That's my line! What are you doing, Polnareff!?When a hero of justice exacts revenge!He must deliver a decisive line with a cool lookWhy are you losing your cool? You look scary... Like you're avenging your parents by taking it out on that old hag.Justice #16I just saw you about to punch an old hag with your fist!It's to avenge my younger sister! But close enough!Right now, you're nothing but the bad guy!Why aren't you using your Stand? Are you not a Stand user of justice?