This isnt any race, this is race is jokingly called the funriders world championship 
If you meet a roadie in South Africa one the first questions that comes up is 'Have you done a sub-3, Argus (now called Cape Town Cycle tour. Its 109 km road event, extremely scenic, over 35 000 entrants (worlds biggest timed event) and 1220 m (4000 feet) of climbing. Its been running for 42 years with it being canceled once 2 years ago due to people blown off their bikes. Cape town wind storm. Cape Argus 2017 cyclists blown off bicycle - YouTube
But one thing interesting is that with the same race different approaches might be more suitable for different riders. My friend with a 4.5 w/kg has a vastly different time and maybe energy system to me over those climbs and my father in law, bless his soul and 115 kg body, also different as these are alp du huez climbs to him.
Top 2.2% does sound better than top 580, thanx @mcneese.chad let’s forget that most of the riders only take their bikes out of storage once a year for the world champs!