The theory is that Dugin's strategies (outlined in "Foundations of Geopolitics") were widely implemented in the US in 2015-2016 in an attempt to destabilize the west.
Wikipedia:
> The book emphasizes that Russia must spread anti-Americanism everywhere: "the main 'scapegoat' will be precisely the U.S...Russia should use its special services within the borders of the United States to fuel instability and separatism, for instance, provoke "Afro-American racists". Russia should "introduce geopolitical disorder into internal American activity, encouraging all kinds of separatism and ethnic, social and racial conflicts, actively supporting all dissident movements – extremist, racist, and sectarian groups, thus destabilizing internal political processes in the U.S. It would also make sense simultaneously to support isolationist tendencies in American politics".
Facebook, Twitter, and other platforms became publishing platforms for active measures (propaganda and disinformation) campaigns to promote Russian-style authoritarianism and diminish the influence of western democracy.
Once these platforms were given this evidence (widely published and released online by the platforms themselves), they took some steps to stop it.
Notable examples include populist movements such as the Trump campaign, state secession movements, white separatist movements, and more recently anti-vax movements. There are many more.
Facebook in particular has failed to stop the spread, and the site is widely considered by most outside experts as "captured" by foreign assets. This is especially true when it comes to QAnon and anti-vax content, which appears to be promulgated to harm western institutions.