If the cable is anchored at the first caliper then how does it still move after leaving the caliper?
For this arrangement to function we must conclude that the cable is only anchored at the end of the second caliper. Imagine if there was no cable housing between the first and second caliper. The cable would still span the same loop but clearly not be pulling the second caliper closed. So if the cable is anchored in two places, even with any arrangement of brakes in between the length between those two anchors will not change.
Don't look at the cable position moving but instead the distance of cable between the two brakes. It can only change if the first brake is positioned with a cable stop (in this case it appears to be a barrel adjuster) allowing the cable to travel independent of the housing.