I think about it like this: what would happen if you did this manually, at the same scale? If I went around asking every single person you've ever met if they could provide any pictures in which you're in the background, and collected them all and sold them as a collection, i'd be borderline harassing/stalking you. Not necessarily straight up illegal, but maybe in some ways? That's what this is, digitally.
My theory is that it began with the discovery/utilization of new oil sources in the US 5-7 years ago. The price of oil crashed by 50% and stayed there for most of the last five years. Many countries around the globe dependent on oil (parts of south america and the middle east) had economic turmoil beginning five years ago, resulting in refugee crises (venezuela, syria, etc.). Refugee activity helped fuel dormant nationalism rhetoric in europe and america, leading to Trump/Brexit, and other movements gaining steam.
Oil discovered -> oil price crashes -> oil countries crash -> refugees flee to us/eu -> nationalism