Answer:
Because a steel rod is a good conductor which would make the charges produced to cascade easily from one end of the metal to another.
Step-by-step explanation:
Charges are formed whenever an object gains or losses an electron. This can be easily produced by three major methods; friction, contact and induction.
Conductors, e.g metals (steel), are materials that would allow charges, electric current, or heat to flow through them easily. They have low resistance.
When a steel rod is charged at one end, the charges cascades from that end towards the other end because of the conducting property of the metal. Thereby it is very difficult to charge one end of the steel rod, while the other remains uncharged.