Spain is the biggest producer of olive oil in the world. And we use it quite a lot (note: of you haven't tasted it, try bread with some olive oil and tomato).
Heavily consumed in Portugal too. Already bunch of news around about how expensive oil is going to be. Totally the new normal. It's not surprising crops going crazy with weird weather, both too much and sudden rain coupled with crazy drought. Last year we already got similar situation.
Honestly, even at Spain you would think they would find something lighter and more concealable. It's like in the US when people were stealing multi-gallon bottles of detergent. If the store owner does decide you're worth going after what are you going to run with that? Price per volume chocolate bars would make more sense. Hell, steak would make more sense.
I don't know, stealing out of necessity would probably lead me to picking a smaller bottle of oil more often. Trying to run out of a store with 20 lb of oil seems to be a more problematic choice.
Detergent was targeted because it has appealing qualities to it and stores weren't putting that much energy in stopping it.
Detergent doesn't spoil or melt like steak or chocolate.
In some markets, it is relatively easy to flip. It was also being used as a way to launder money, since you could ship stolen detergent into Mexico to be sold in Mexico. No one was really tracking detergent shipments into Mexico.
Olive oil is the most essential ingredient to cooking and living around these parts of the world. There's barely any cooking you can do without it. Literally everyone has to have it.