For the record, I don't think this has anything to do with the U.S., false dichotomies are a more or less equally common human shorthand anywhere and anywhen that I've visited, or studied at all.
I've assumed it's because people don't have time or energy to consider all the nuances of everything all the time, or the space to list them out. The brain is in many ways a device for ignoring anything that doesn't help you get food and not get eaten by a lion.
There really seems to be some dteong cultural tendency to do this.
Compared to NZ's politics... which is more like a blob of parties which sit pretty close the centre, and sometimes parts of the blobs move more left or more right.
But naturally the dichotomy comment doesn't hold true in all circumstances.
A lot of the polarisation in US politics is probably due to the two-party system. I don't know whether or not that has anything to do with people thinking in false dichotomies in other contexts.
I try to have conversation about complex issues all the time and those conversations never advance past basic talking points that any person who spent time actually looking into any topic would not reduce down to a binary answer.
Half the people I talk with think I'm super liberal and the other half think Im super conservative and it stems usually from the first interaction Ive had with people where Ive tried to advance a topic to beyond repeating the same lame talking points, but it really never gets past first base.
So you might as well talk about more trivial but lighter things.
I know that I really love to deep dive into things and pick things apart. But my girlfriend hates it when I get like that, so I learned to understand her point as well.
That said for topics I do have some more in-depth understanding (and opinions on), I've started to find discussions around them to be... draining. People seem to want to argue or 'discuss' things heatedly, but that's it. It never leads anywhere or to any meaningful change in behaviours. Not that I'm trying to influence anyone, but it just feels like arguing for the sake of arguing. I'd rather just keep to myself at that point.
You are aware that you are creating a dichotomy right here, no?
You might find this interesting: https://en.wikipedia.org/wiki/Binary_opposition
One way to think about is that given a set of items, you want to understand them by finding both commonality and distinction between them. Partitioning into two sets is the simplest form that accomplishes some of both.
If you lump them all into a single set, you may have a sense of commonality, but you've learned nothing about distinguishing them.
If you put each element into its own set, you have distinguished all of them, but learned nothing about what they have in common.
You could form the elements into pairs, but the it's not clear what to do with the odd one out if there is one.
Given multiple items, you can always split them into two sets and how you choose to do that reflects both what the elements in each set have in common, while also showing how the two sets differ.
I suspect that binary opposition is in some ways fundamental to cognition. It certainly shows up profoundly throughout all cultures across all history: sun and moon, night and day, yin and yang, god and devil, woman and man, earth and sky, etc.
If there are 3 teams, and one team starts to gain an advantage, the other two are highly incentivized to join forces to defeat the larger one.
Unless you design systems to allow smaller teams/parties/groups to flourish, most competitions will devolve into two sides. In voting this would be things like ranked choice or approval voting, rather than single vote "first past the post".
P.S. Recent success with AI for Diplomacy at DeepMind:
https://www.deepmind.com/blog/ai-for-the-board-game-diplomac...
No thinking required. Your side is the "correct" one and so you have moral superiority.
Fundamentally, this is a typical strategy for the human mind and even organisms in general, to understand the world by categorizing it into opposing pairs: light/dark, hot/cold, life/death, up/down, left/right. This is often discussed in Buddhism, for example, there is a whole school of tradition called "Not Two" that focuses on going beyond this illusion of duality.
About how polar opposition seems to be stronger in the U.S., in my opinion that's due to the weaponization of culture in the country, how the media is used to manipulate the public into outrage and conflict. It's a form of social control that's pretty much everywhere, but it seems to have especially reached a boiling point in the U.S. in recent years.
It's a primitive, simplistic and reductive way of looking at the world, ignoring the spectrum in between the opposing sides, which are arbitrary anyway.
Maybe there are introverts, extroverts, various mixtures between, and even hyperverts or transverts who prefer one side or the other depending on their mood or life stages.
I agree that it can be dangerous if you create a false dichotomy, because that can lead to a misunderstanding of how something works.
Many normal people are social when they feel good, and less so when they are not.
But extraverts have learned to use social interactions to "fix" their emotional state. Or maybe they are born with it. However they deal with social aspects completely different.
I think most of us are in the middle. Where some of us lean to less social, but I think part of that is emotional issues that haven't been dealt with. Whereas extraverts are just different.
Categories are good for introduction, nothing more.