The routing table in the exhibit shows two default routes (0.0.0.0/0) with different administrative distances:
The default route through port2 has an administrative distance of 20.
The default route through port1 has an administrative distance of 10.
Administrative distance determines the priority of the route; a lower value is preferred. Here, the route through port1 with an administrative distance of 10 is the preferred route. The route through port2 with an administrative distance of 20 acts as a standby or backup route. If the primary route (port1) fails or is unavailable, traffic will then be routed through port2.
Regarding the statement that the port2 interface is marked as inactive, there is no indication in the routing table that port2 is inactive. Similarly, all the routes displayed are not necessarily installed in the FortiGate routing table, as the table could include both active and backup routes.
Reference:
FortiOS 7.4.1 Administration Guide: Default route configuration
FortiOS 7.4.1 Administration Guide: Routing table explanation