Russian trolls aside, millions of people voluntary and completely for free (as a beer) spent much more time kvetching about politics in 2016 then in 2012 or 2008. There should be a reason for it.
In Western Europe the amount of kvetching is ten times lower on average, meaning people really care about elections 4 weeks before and 4 weeks after and then move on with their lives, as opposed to US, where political fighting is never stops.
My pet theory (which may cause downvotes here) is that US democracy seriously differs from Western Europe. In Western European countries you have different parties with their different pet issues, but you don't have different ideologies.
In US, there are two different ideologies, having different views on everything -- gender, religion, race, well, any topic you can pick, actually. What we observe is these two ideologies maturing, crystallizing and diverging from each other.
I often wonder how it will play out, in a long run. ;)