You got it wrong, there are few types of outlets onboard airplanes:
Utility outlets: They are used by the ground/fleet services to clean the aircraft on ground prior to passengers boarding. Usually it will be used for strong vacuum cleaners which requires higher voltage/frequency and can damage electronics not designed for these outlets. This is the type mentioned in the paragraph you quoted above.
Shavers outlets: These are found in lavatories, they are designed for electronic shavers and can be used only for shavers.
In-seat outlets: These are embedded in the passengers seats and are designed to be used with personal carry on electronics (laptops, phone chargers...etc). Usually they are deactivated during boarding, take offs and landings and activated during cruise only. This is what you should use and it is available in most major airlines including Cathay Pacific. Also it is mentioned in the same page you linked:
In-seat power will soon be available across our entire fleet for the devices mentioned above. These in-seat power ratings are however not designed for use with medical devices such as CPAP machines. Passengers must provide their own batteries that are sufficient to power medical portable electronic devices.
