Facebook feeds and Election results?

As I mentioned in my previous post about Liz Cheney, I thought it might be worth looking at Facebook posts before an election to see if I could find anything predictive. This first look did not, and I realized how much work people do to understand elections.
I looked at two races that flipped from Democratic to Republican, the California 21st district and the Iowa 1st. Two races are not enough data to determine any patterns, so I may look at more over the next weeks.
I wanted to see what their facebook feeds looked like before the election, so I looked for Facebook pages that were campaign pages, rather than personal or politician pages. One page is for the politician and not her campaign, because she did not appear to have a campaign page. The four politicians are TJ Cox, David Valadao, Ashley Hinson, and Abby Finkenfauer. For each one, I checked how many posts they did on October 31st, how many reactions, comments and shares each post got and for one of those posts, what the comments were like. For simplicity, below are the most popular posts for each politician from October 31st, 2020.

At first glance, this shows a clear preference for the winner on social media. Both winners have more reactions, comments, pro-comments and shares. A deeper look at the voting in both districts, however, shows that both races were closer than these data would suggest. These data are from Wikipedia (District 21 and District 2) and APM Research.

I keep looking at these data and thinking about all I don’t know. I had no idea that voting districts had such different numbers of voters in them (both districts have 800,000 people, just a different number of eligible voters). Turnout is obviously critical in District 21, although in 2018, TJ Cox won with lower turnout and by 862 votes (57,239 versus 56,777). Demographics probably also play a role, and may impact which social media people use to communicate with candidates.
I need to do more research. I have many questions — Do all races reflect this same preference for one candidate? What about races where the primary was more important? What role does race or ethnicity play in shaping elections and social media? What did the polls say about these races around this time? What happened earlier in the races? I’ll see what I can answer without getting a degree in political science.
**Correction, and earlier version of this story, mistakenly said that no Democrats won a formerly Republican seat. In fact, three Democrats won districts previously represented by Republicans.