In 2012 FB was trying to demonstrate their usefulness and centrality to political campaigns. They had teams working with both Romney and Obama on data analysis, outreach, and more. Some of my husband's peers were involved in this effort. And at the time, data analysts were also beginning to warn about where this could lead. Obama's people were much better at it than Romney's; OFA had a head start from 2008. Crucially, neither campaign violated the terms of their agreements with FB. As the Obama outreach woman discussed, everyone was simultaneously trying to figure out what was possible and what was ethical. As we all know, when tech capability reaches and surpasses our moral code, we have a problem to catch up and address.
Between 2008 and 2012 iPads were introduced and smartphones began adoption. This obviously opened up many, many more users to online platforms and created much more data to be harvested. This has been the Wild West for the last 10 years, and very few actors have been able to keep up. Certainly not Facebook, Twitter, or the US government. They've had to continually play catch-up as the potential of these platforms became apparent. That is why FB changed their terms to prevent third parties from accessing friends' data.
Russia and Israel, in contrast, early on recognized the possibilities. Actors like troll factories, data mining operations, etc., were pioneered by Russia.