It looks to me like as usual with these incidents it will be a series of events that causes the accident. Digging around some more, I see there is berthing barge next to the ship. That suggests to me the ship was nowhere operational. An update to the article says the Halon gas fire suppression system was turned off. Combine that with a skeleton crew on the weekend, it was likely a recipe for disaster.
No, they stated it wasn’t anywhere near operational as they were going to be ripping the flight deck up to replace/rebuild it and had already started dismantling procedures. The drydock period it had just had was to do normal overhaul procedures and it was immediately taken over to its current pier to have the deck work done. It wasn’t going anywhere soon.
That is almost always the way it is with these things, but...it is good to keep in mind that deliberate arson is not unknown in these things, as other posters have pointed out.
Also, it is pretty clear the ship was non-operational and undergoing a refit. I wouldn’t be too harsh on the skeleton crew if you had a nasty fire like that and there were only a small number aboard...particularly if the person in charge on board was a somewhat junior officer with little experience.