Where do you find these BS stories? My first cruise was in June 1988. My 37th cruise is coming up in September.
Not once in my previous cruises, neither me or my wife, or my 2 kids ever had norovirus attack. My kids did 16 cruises with us before going on to college. We got slightly sea-sick only on one cruise which was the smallest ship we ever sailed on. The sea-sickness lasted barely 24 hours. The other 6 days on cruise were very enjoyable as usual. Now we stick to ships bigger than aircraft carriers, which is most of them now-a-days.
Not only I never got any gastro-intestinal problems ever, but I always came back feeling stronger with the amazingly high nutrition cuisine aboard the ship plus opportunity to exercise much more than in my home life. A recent cruise on Oasis of The Seas, it was 1/2 mile walk from our cabin to our dining room and back. Since we prefer dining room over buffet for all 3 meals during the day, it was 1.5 miles walk everyday just to go eat. And the ship is so huge, I easily walked 3-4 miles in addition. That ship actually has a living forest on board and birds are living there permanently.
Never been on any cruise. Worst case was a two hour ferry ride.