Sheesh. Why should they do that. What has the cdc got to do with anything when it comes to a European citizen testing positive for covid in Europe, several days after they get home from a cruise on a Maltese flagged ship sailing in European waters?
I guess some people are just never going to let this go are they.
If you're so worried about covid, don't cruise. It's never going away, people will be catching covid on cruise ships (and everywhere else in life) forever more. The vast majority of people are just getting on with things now and not spending every waking moment worrying about something which currently has a mortality rate of less than 0.02%.
Cruising has to get back to normal, at full capacity, with minimal or no restrictions (like everything else) otherwise the cruise lines all go bankrupt. If you don't like the idea of ships at full capacity, don't go. It's that simple.