No one has ever eaten an olive off the tree and enjoyed it. Raw olives are inedibly bitter, mainly because of oleuropein and its aglycone, and to make them palatable they must be cured and fermented so that a substantial amount of those bitter phenolic compounds is removed. How much gets removed, and how, is entirely a production choice. Lye curing takes a few days; brine or salt packing takes months, during which lactic acid bacteria acidify the fruit. Those routes do not land in the same place, which is why a cheap canned black olive and a brine-cured Kalamata are barely comparable objects. That is the practical source of the split. Most Americans who say they hate olives have usually met the standardised, heavily processed kind, often sliced onto something else, while the people who love them are usually describing a differently cured fruit. Olives also have one of the smallest neutral blocs of any food YouGov tested, at 12%, which is the signature of an ingredient people notice immediately and rarely shrug at.