No he was wrong the torque is reacted to the FRAME through the pin and pivotThe wheel torque is reacted to by the frame through the swingarm. Physics 101.
The motor is invisible to the frame if it's centered on the swingarm pivot. All forces are purely between the motor and wheel and the reaction to the motor torque is by the swingarm lever acting on the axle pin. Not the swingarm pivot. The torque of the motor is translated to the wheel. You coupd argue that the motor is pulling on the chain which lifts the frame at the swingarm pivot, but that is defined as wheel torque.
So, he was correct.