Don't generalise... there are natural ways of processing olives (direct brining) where microbes do the de-bittering , breaking down oleuropein into non-bitter hydroxytyrosol, with no water wastage, (fermentation brine can be re-used as packing brine). The beneficial antioxidant hydroxytyrosol is then still available for consumption in the olives as part of a delicious natural traditional food, instead of going a roundabout synthetic way and then having to pop pills.