One article I read said that numerous issues colluded to make it much worse than it would have been at sea.

Because it was there under maintenance:
Lots of doors were open and had hoses/wires/whatever going through them, so they couldn't be closed off to isolate the fire.
Skeleton crew
Lots of extra maintenance/cleaning stuff laying around that wasn't normally there, ready to burn.
Fire suppression systems may have been turned off for maintenance.

Bad situation for sure, but not really relevant to what would happen at sea if a fire broke out.