Anti theft security lock is on after replacing the ignition switch?

Yes, changing the ignition cylinder can cause you to need to program in the keys. The pass lock system uses a sensor that goes around the cylinder and that is triggered by a magnet on the cylinder. If the cylinder is changed out using the key to turn it and releasing it with the pin under the lock, you usually don't need to program the system. If however, it is drilled out or removed by force, then you need to replace the pass lock sensor and the outer ignition case as well. There is an anti-tamper section that can trip and lock out the ignition.
I would try the 30 minute relearn and see if you get lucky.
For that you want to be sure the battery is fully charged. Then you start with the key in the ignition, all doors closed.

30 Minute Learn Procedure

1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON.
3. Observe the SECURITY light, after approximately 10 minutes it will turn OFF.
4. Turn OFF the ignition and wait 5 seconds.

Now repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes
Once you do the third cycle, try to start the truck. If it was successful, the engine will start, and the security light will go out.

it did not work.

Then you will likely need a scan tool or a mobile locksmith to be able to use it to program the replacement into the system.