Must have been thinking to himself "Tonnes of guys that could have taken this guy down and they're relying on me again to take him out. I could be at home taking care of my only child, loving wife and mother and elderly grandparents, while writing my thesis on starfish, but nooooo, I gotta play Sherlock Holmes for these asshats that can't do shit. I thought I'd be finished with this shit after trashing Dio, then they go out of their way to bring back horrible flashbacks with that kid getting donuted, think I'll make it up to him with a vacation to Italy, that'll be nice. Where was I? Oh yeah! ORAORAORAORAORA!!!"

Jotaro was just busy writing his thesis 90 percent of the time while in Morioh.
The thesis is called: "How I met these bomb-ass starfish in morioh"