If you read the whole thread, I would not have to spell this out. These are preservatives (source):

• honey
• salt
• garlic
• sugar
• ginger
• sage
• rosemary
• sage
• mustard
• mustard seed
• cumin
• black pepper
• turmeric
• cinnamon
• cardamom
• cloves
• vinegar
• citric acid
• lemon/lime juice

They generally work by killing/repelling/deterring microbes that to a notable extent happen to be of the unwanted variety. Before yesterday, I thought salt worked similarly to the others on that list. Yesterday I learnt that salt is uniquely functions as a preservative due to a different mechanism (a drying effect).

Your logic is nonsense. To claim that because substance X does not kill /everything/, it cannot serve as a preservative -- this is broken logic that you brought to the thread. Nothing on that list of food preservatives kills or deters every microbe - not even every harmful microbe. Of course they selectively mitigate /some of/ “the bad bacteria” (but note it’s a bit straw mannish for you to use the article “the” in your phrasing imply /all/ unwanted microbes). Most preservatives mitigate enough unwanted microbes without unacceptable overkill to beneficial microbes to justify use as a preservative. They are selected as preservatives for this reason. Foods that fail to significantly select against unwanted microbes (i.e. most foods) don’t get tagged as a preservative. How are you not grasping this?

You also have noteworthy bad assumption: that evolution does not happen outside of the ocean. The claim that because life started in the ocean, the ocean is therefore suitable for everything -- this is bogus. Try putting a freshwater fish in the ocean. If a complex organism can evolve to become intolerant to the environment of its ancestors, why wouldn’t microbes also evolve to develop intolerances?