Three quarters of the news we read about cruising would not be considered "news" in any other context except that it is cruising.
This made the mainstream news because it was an "If it bleeds it leads" type of story. Crazed employee attacks boss is something that would probably make it on the news in many markets.
You never see a news story about "IT employee finishes program update to BT281" or "Teacher goes through entire day with no incidents". Now if that teacher goes ballistic and hits a student or another teacher or the IT employee goes postal then it's news.
Cruise ships are closed and a somewhat mysterious environment to most people and the cruise lines give the impression that it's one big happy family. When something happens that goes against this image it's news.
I guess the news people need to concentrate on the real news like Kim Kardashian's divorce.