My personal guess is that "The Base" is at it's root a Russian operation hoping to stir up more FUD and tension in America. It's like buying a lottery ticket. Low cost to implement, low probability it'll work, but if by some slim chance it should, the payoff is huge.
Just like how they did actually attempt to manipulate the 2016 election. They had no hope of actually swaying the outcome, IMO they were as surprised by Trump as Hillary was... but in a meta-sense the manipulation itself was the goal. They're not going after any specific outcome other than to undermine American civil society.
Of course this segment of the Russian FSB or whoever they report to, they're subject to their own operational biases. Anybody could just tell them that if they really wanted to harm America, they could just pull in the same direction as the MSM and root for the Left here. And of course they'd go unnoticed too.