First, to get this out of the way: Russia isn't doing anything special here. They're not creating the divisions. They aren't responsible for those divisions existing, even. They're merely exploiting them, like any other hack. Our 'psycho-security' for lack of a better term is as flawed as our cyber security, with way too many vulnerabilities left in because it's easier that way. Why patch the flaw when the ROI isn't there and it makes it easier for the actual users of the system to manipulate us (critical thinking? That causes you to question the constant advertising and that might make you buy fewer stuff!). Blaming Russia for all our problems is a copout and doesn't actually address our problem. It just lets us point the finger at somebody else.
That said? We can certainly use a layered strategy -- dare I say Defence in Depth -- to deal with our problems, and going after Russia is a valid response. If we can block them funding Alt-Right parties and memes/ideas, that's less bullshit to bombard people with. It's not the total answer, of course, but every dollar taken out of circulation from Russia going to Jill Stein, Junior, and of course Trump and his flying monkeys, is one fewer dollar funding an ad campaign or paying for dishonest posters who say we should vote Third Party because Dems aren't tough enough on Israel. Again, we'll still get a few of the True Believers and self-funded kooks (qooqs?) posting that bullshit but their reach will be limited. This is good for all of us.