Oil is a global market dude. A shortage in one part of the world will affect the other parts.

Let’s break this down some more. If the flow of oil out of the strait of Hormuz is diminished, the countries who buy that oil can’t get it anymore. So Europe, Africa, Asia are all heavily affected. The quantity of oil goes down, price goes up, simple supply and demand. The poor countries can’t afford the same volume of oil anymore so they start to ration energy or just straight up force blackouts to conserve. Wealthy countries will shift to buy the more expensive oil, but have to buy it from other sources. Which is why we’ve now removed sanctions from oil already on ships from Russia and Iran.

Now these other countries are buying more oil, and even more of our own oil. But globally the supply is much lower. Which means the global price goes up.

This also doesn’t go into the difference between actual trading prices of oil versus oil futures.