The route controller's callback for losing leader election exits the controller:

https://github.com/openshift/route-controller-manager/blob/main/pkg/cmd/routecontroller/route.go#L67

MicroShift embeds the controller, and needs it to stop without exiting the entire process so other controllers have a chance to shut down cleanly.

Other controllers may use the library-go function ToLeaderElectionWithConfigmapLease which also calls exit:

https://github.com/openshift/microshift/blob/main/vendor/github.com/openshift/library-go/pkg/config/leaderelection/leaderelection.go#L81