Your scepticism is well warranted. The advice is wrong.

Brushed motors are simple dc motors, and the controller simply adjusts the current and voltage available to the motor to control its speed.

Brushless motors are in fact 3 phase AC permanent magnet motors. The controller adjusts the output power's frequency, voltage and current to control the speed. Tying any 2 of the 3 output leads together would short that phase out, smoking the controller. The ac power to the dc motor would result in humming before the smoke billowed out.

J