When they say “the compressor is energized” they don’t mean that the shaft is rotating, they mean that a small current is being run through the windings to generate heat and vaporize refrigerant that pools in the compressor sump. Many HVAC systems have this feature, especially ones that are designed to operate in winter conditions (heat pump or low-ambient cooling). Usually the feature is implemented with a separate resistive heater element attached to the compressor housing, but Mitsubishi is being clever here and using the actual motor windings as the element.
Also note that many mini-splits with heat pump or low ambient cooling capability will also have a heater element in the bottom of the case to keep the drain holes there from freezing up.