In this video on severe contango the author says that if the spot price is way under the futures price, a lot of people will buy oil on spot price and enter a short position. Then he says :
...it's going to increase the supply on the selling side of the future's contract so to lower the future's prices.
I thought the futures price was fixed at regular interval based only on the spot price with compounding and some extra costs, but not supply and demand on its own market. So how the high supply can lower futures price ? Because if the spot price raises, then the futures price should also raise, other things being equal. What am i missing ?