

Because they’ve been working to stir dissent in the US and it’s been their playbook since the late 90s
https://en.wikipedia.org/wiki/Foundations_of_Geopolitics
Russia should use its special services within the borders of the United States and Canada to fuel instability and separatism against neoliberal globalist Western hegemony, such as, for instance, provoke “Afro-American racists” to create severe backlash against the rotten political state of affairs in the current present-day system of the United States and Canada. 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 sectariangroups, thus destabilizing internal political processes in the U.S. It would also make sense simultaneously to support isolationist tendencies in American politics”.
Literally the second google result. (And probably is linked to in that reddit thread but I refuse to use reddit)