Because the ‘total elevation’ to which you are referring is the amount you have to climb (presuming you start near the pens) to get the badge, whereas the elevation listed for the route is the elevation for THE ROUTE, which is a loop that repeats over and over again if you keep riding and don’t’ make any manual turns. If you ride the route you will never go back near the pens again.
I’m not saying that the elevation guidance couldn’t be a bit more clear, just that the listed elevation for the route itself is correct.