It has been nearly ten years since I played vanilla. My god...how annoying would that be? How could Bethesda think that would be a good idea?
For all my eleventy billion and two mods, I still play with mostly vanilla creatures. And let me tell you. I hear the cries of hostile cliff racers in my dreams. (You'd think I'd get a mod to fix the vanilla creatures thing, but I never have. Never particularly wanted one either. I think the cliff racers might've driven me around the bend.)
I still camt wrap my head around that the cliff racers drove the dragons away but the one dude on the boat drove the cliffracers away....
Well, it's obvious, isn't it? Cliff racers annoyed the dragons so much that they had to leave or go mad. And Jiub has become some sort of memetic badass for some reason, so of course he'd have the power to drive away the most annoying creature in all of Vvardenfell. Presumably he did it just by staring at them.
And then after driving off the cliff racers, he punched out Chuck Norris.