Yes on A. The racists in the 50s and 60s initially were Democrats. They didn't become socially "conservative" and Republicans until Nixon's Southern Strategy fed them "family values" messaging. Once social conservatism seeped into their mediasphere the metamorphosis was complete, hiding behind "soft" racism and bigotry.
Hippies, violence in the streets, burning of cities, AK-47 carrying Black Panthers, Manso family types, radicals and revolutionaries of many stripes. Every damn week in the 70s some 1%'er leftist crackpot on the west coast was up on a roof with a rifle and/or dynamite.
Post Reagan pitchfork right-leaning activists (anti-brown, gay, secular), militia nuts, and eventually mass shooting whack jobs have been typically white and far-right.
Sirhan Sirhan is a Palestinian/Jordanian (really the same). RFK Sr. supported Israel. That makes Sirhan Sirhan a foreign element - not from the American left or right.
FWIW, far, far left governments = far, far right governments in practice. Communists and fascists racked up at least 130M deaths in the 20th Century. Invariably, a handful control the power. Power corrupts and leads to tyranny and violence. This is a grave part of the danger with Trump's attempted unitary executive branch take over, with his accomplices in the GOP Congress and SCrOTUS.