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You realize that the star difficult looks at neither AR nor OD right? It simply looks at the physical aspects of the map such as speed of jumps, distance of jumps and circle sizes. Also, that songs doesn't have any 280 BPM streams, only single taps. Those could be played as 140BPM streams. If it was 140BPM, would you then think it still so hard? I doubt so.
Anyway, everyone knows that the star system isn't perfect but it's a damn good difficulty rating as far as I can see. It'd be impossible to make a perfect difficulty system.