For this website in particular, they are only measuring the speed of the vehicle as it enters the slalom and not exit speed or total time taken. They are effectively measuring how aggressively electronic stability control will intervene to slow the car down so that it can safely pass through the cones.
For instance, I don't think the
2018 Opel Grandland X (a crossover) handles nearly as well as a
2016 Porsche 911 Turbo S in any realistic scenario, but they both were measured at 81 km/h.