Only $100,000 in FB ads by Russians got people upset, but $1.8 billion in FB ads for 2018 elections- mostly by big oil, big pharma, and Wall Street. There are no election rules or requirements of truth or limitations on FB ads. And no one except the intended see them, so it is hard to know about or counter lies. In Trump's election, the vast majority of the pro-Trump FB ads were by big corporate players, not the Russians.

https://truthout.org/articles/1-8-billion-in-unregulated-digital-ads-could-sway-midterms