Secondly, poor standards of food hygiene with many catering staff from countries with flexible standards. Lack of refrigerated displays for help yourself buffets and the like.
I've been on 5 cruises with P&O (the last 2 years ago) and long before Covid was even a thought, hand-sanitising was strictly enforced on entering the dining rooms and widely used when entering the food servery areas in the buffets.
Cleanliness on board always seemed pretty good to me and I never experienced any onboard food-poisoning outbreaks or anything else.
As usual, it seems to me that you look for the negative in order to support your belligerent views, rather than the reality, which is that the issues you describe (including a cruise ship encountering a storm) are fairly rare.
My experience of the latter is that it's sometimes a lot rougher outside than the ship will make you feel it is.