You have to realize that when this happened, as the article says, Spain was just out of a dictatorship. Back then, freedom in the press was... Poor, at least. S

You have to realize that when this happened, as the article says, Spain was just out of a dictatorship. Back then, freedom in the press was... Poor, at least. Specially, there was still a lot inertia going with "The press must follow the government line". In my opinion, it was as the article says, right or wrong, somebody found the "canola oil" hypothesis and it was really convenient: with the same shot, the recent and weak vegetable production was protected and a competitor for the national olive oil was smashed. Today, I guess that there is in nobodies interest in Spain to move the issue. Everybody is completely convinced of the "canola oil version", and the vegetable production is a sizeable part of the Spanish economy. Saying the contrary in Spain in polite company it's the kind of thing that would label you as a tin-foil conspirance theorist.