People who hold billions in derivative bets on higher wheat and soybean prices are also buying the companies that stock grains. They are taking wheat off the physical market to manipulate the price upwards and to profit on their bets while elsewhere people die of hunger. Today such behaviour is legal.
You probably thought spot prices set the futures prices. Nope, it’s the other way around. Thus, spot prices in any commodity can and are manipulated by speculators.