I feel like your post is very US-centric and that is a big part of the misunderstanding.

Facebook should not be so focused on one country. And they are not: some of the problems were visible for the Brexit and the subsequent parliamentary vote in the UK; they have already addressed some issues with recent the French and the German elections. There certainly are many more elections before November, see:
https://en.wikipedia.org/wiki/National_electoral_calendar_20...
and there was a handful of Special ones the US.

Facebook leadership used to be too US-Centric and I was very happy to see during the US Congressional hearing that it had changed (their counsel was trying to explain but failed). The reason it matters is that this means that they cannot a custom-build solution that assumes that the issue is:

- Fake News: the issue is, depending on who you ask, raise in inequality, more international migrations, the rise of populism, a systemic challenge to the Nation-State; the problems go from raising tension between political groups and non-constructive political speech; normalisation of racism; the expansion of satire beyond recognition; the two-step of outrageous statements, partial correction and dog-whistling; acceleration of political news cycle; leverage of non-factual or non-representative statements for political inflammation; etc. The over-simplification or confusing all that into that lumpy bag of a concept that is “Fake News” is highly problematic, even if you focus on one country.

- preventing outside interference: that’s actually a lot easier without so much corporate money: massive ad campaigns, or ads-only approach is mainly a US problem; creating puppet accounts and using them to discredit a group, or pouring more oil on the fire is more the type of vector we have seen overall. That is generally done training local volunteers as was seen in France, or apparently almost entirely internal influence, as was seen in Germany.

- ban fake accounts: Facebook has been fighting fake account forever, so yeah, this is clearly a problem; but the issue is that there is no clear definition of fake. To simplify greatly, you have:

1. people who use a modified version of their name (no one cares);

2. people who have two accounts (justifiable but made harder by 1.);

3. people who do 2.) to have a raging account where they exposer views on race, gender and religion that their friends and relatives would not accept (certainly some cases where that can be justified, like closeted gays);

4. people who do 3.) whose other account is deeply hateful, threatening or just plain dickish (we are getting close to banning territory);

5. people like 4. whose other account was blocked or banned so they set up a new one to keep on talking about how smart Hitler was (see where this is getting?) and how they are going to act on his ideas;

6. people like 5. but who know how to code and preventively create more accounts because they expect the first dozen they created to be blocked soon;

7. people who are better developers than 6. and offer to help them creating many realistic-sounding people who like to comment about the upsides of Slavery, below advertising for the NYTimes;

8. people who learned how to do 7. but figured out you could make money off it — of more simply, who went straight to that step.

And for 9. people who figured out you get more, less scrupulous friends faster if you use picture set scraped from porn sites.

The direct advertising loss from fake accounts is presumably massive; the loss of targeting relevance probably much bigger; the loss of trust and long-term profit orders of magnitude bigger -- so you are right to think this matters to Facebook, but for the right reasons. It’s just not simple, not exclusively politics and certainly not a problem that should be though as US-vs.-Russia. It’s much more complex.

I mean, Facebook even has to consider how to protect the integrity of the Russian election later this year. OK, that was a joke.