The irony here is that Gilens and Page specifically do not make the claim that "the US is an oligarchy". The claim they do make is that it exhibits a certain a

The irony here is that Gilens and Page specifically do not make the claim that "the US is an oligarchy". The claim they do make is that it exhibits a certain aspect of oligarchy, and even in this, their specific subclaims are quite reserved. But at no point do they flat-out say "the US is an oligarchy", as a label. Likely for the most obvious reason, which is that no one has a precise definition of what that means. From its very nature, it's an untestable assertion. But news outlets like the BBC did pick up that label, and happily churned out articles with headlines saying "The US is an oligarchy, not a democracy". To make it, you know, easy and intuitive for the regular person to understand. Which apparently lots of people caught glimpse of, and thought to themselves: "Yup, that's what I've always thought. And now it's proven by science."