Why does the rear wheel of a motorcycle tend to lock when braking rather than the front wheel?

Your answer is correct. When braking, most of the motorcycle's weight shifts forward due to inertia. This increases the load on the front wheel and reduces the load on the rear wheel. With less weight on the rear wheel, it has less grip and is more likely to lock up if too much brake force is applied. This is why the rear wheel is more prone to locking during braking, while the front wheel—with increased load—can handle more braking force without locking as easily. Always remember to brake gently and progressively, using both brakes and being aware that the rear wheel is more sensitive to locking.