Why was KITT never equipped with heavy duty weapons like rockets, grenades, machine guns,lasers etc?
I realize his primary duty was to protect human life, but it could have made things a lot easier against the bad guys.
You said it yourself - he's programmed to protect human life without the use of deadly force.
Things like grenades and rockets are far too deadly and violent for a PG rated show about "one man making a difference".
Things like the microwave jammer, smoke screen and oil slick usually proved to be sufficient for stopping the bad guys without resorting to violent weapons.