How does this transfer to any other situation involving group communication? Do the people on this board have a right not to see emotional conversations? Not rocking the boat has a place in professional settings, but I don't think people have a right, in general, to not see emotion.
If you think that you have a right to behave how you wish, be anyone's guest. Just don't complain when you don't get your expected result. As that's how etiquette works. Its enforced through social punishment, and often without saying a word.
There are good reasons for most basic rules of etiquette, especially in public conversation. Protecting those reasons is a strong incentive to enforce the etiquette.
You're over-simplifying what I said when you state that people don't have a right not to see emotion. This is specifically in regard to politics, and the greater consequences of spontaneous political conversations including but also beyond being uncomfortable. What I was implying is that said emotion, in regard to politics, too often frequently leads to group tumult. Which is one aspect of why the etiquette exists.
I'm sure you can find people who will go out of there way to argue with you. But to expect random common people in their few precious leisure hours to not avoid you is asking too much, should your preferred topic of conversation be politics.
I was trying to clarify the scope of your comment "infringes on the right of others to not be regularly subject to spontaneous (or not) conversations that people frequently get emotional over."
I've been living in the United States for over 20 years and I genuinely have never experienced/felt such a strong standard for public conversation, even amongst groups of people from different generations. It doesn't represent my experience at all. In fact, there are cultural memes involving older generations who absolutely do not follow this standard. It really paints the group that you're describing as extremely fragile, and I think that's also an implication of the article.
"If you think that you have a right to behave how you wish" No, I don't think I said that, actually.
Given that, I feel like you complaining that it made you feel as if you are "walking on eggshells" is meant to be manipulative toward getting me to concede your desires for the culture.
Good luck with that, anywhere. Believe what I say or not, I couldn't care less care how you feel in regard to my good faith sincerity. For Pete's sake. This is a stranger on the internet. I'm not your mother.
You're more than welcome to ignore what I say. I am not invested in you believing me, and this is not whatsoever a debate. I'm informing you of the reality on the ground as I know it to be. You seem to think that you are debating with the culture through me, somehow. My word.
As for the rest: I wrote a long response and then deleted it because of how crazy your response is on multiple assertions. From the reversal of your prior core complaint (to what, try to marginalize the common etiquette by now saying that you never come across it when it was the subject of your prior complaint?), to the hostile label, to the supposed and pointless correction of my phrasing that requires ignoring that it was in the context of your initial complaint. You are being argumentative just to be so, predicated on a false premise to boot. Your post isn't worth responding to more specifically. It's not hard at all to see why you might have some cultural trouble. Though, given what I now see, perhaps it isn't cultural trouble exactly. Perhaps it has more to due with your specific personality. As I have known many more perfectly polite and conversationally skilled foreigners than not.
If this quality of response is typical of your conversational skill, and refraining from it is "walking on eggshells", then I'd suggest you get used to that in order to get by.
Or maybe taking a communication class would help. A lot of people have stumbling blocks of various types, and not only with the specific issue under discussion. Even those who were born here. Conversation is an artform.
Good luck with the rest of your polite and skilled conversations where you accuse other people of being manipulative and crazy.
There has also been a shift in the focus of politics away from economic policy and the running of government services (as was very much the case in the UK up to the 1980s) to social issues as a result of a centrist consensus on what were important issues - disagreement about them is now purely theoretical and off the table in terms of what might actually change.
It think the problem has also been inadvertently illustrated by people in the comments discussing specific American culture war issues with a great deal of anger.
An aspect of this is the lack of willingness to compromise. Take abortion. It is much less of an issue in most of Europe because it is allowed, but with short term limits. It means many of the arguments for it are not relevant, but it also undermines many of the arguments against it because of lack of functioning brain tissue, or the state of development comparable to a premature baby. Anglophone countries are much more all or nothing - long term limits or not allow at all.
We also do not (even in the UK) have the American alignment of party politics with social issues. Can you imagine the Republicans being the party that allowed same sex marriage?
I think the moving of discussion online has primed people to be more aggressive about their views in general. I was thinking the other day about the people I know IRL who have blocked me on FB: my ex, a friend of hers, one of my ex's sisters (emigrated to the US and is a stereotype Trump supporter, stolen election theory etc.), a creationist (also my ex's sister, a nice person who keeps in touch with me, but does not like my comments on her FB posts), and a remainer/rejoiner.
The American party system is not that similar to the UK's. They are both FPTP but the UK is nothing like as two party as the US. Compare this:
https://pressgallery.house.gov/member-data/party-breakdown
to this:
My personal observation is twofold. First, spontaneous political discussion in the West is considered to be impolite in conversation for valid reasons. The first is the fact that social reactions are unpredictable and, in a casual social situation, rightly the emphasis should be on maintenance of the situation for everyone. To prioritize one's impulse to need to have a political conversation is impolite because it risks the group as well as potentially infringes on the right of others to not be regularly subject to spontaneous (or not) conversations that people frequently get emotional over. Group harmony as well as the individual's right to peace in public are prioritized.
Second, lifelong exposure to propaganda has trained individuals to have highly emotional reactions to those who disagree with them. The political environment in the West is not psychologically designed for casual public political conversation. Everyone knows multiple individuals who simply cannot abide, at least for long, anyone on the other side of the isle. Propaganda's long time goal has been to encourage mental illness to be viral, and it has widely succeeded.
An acceptable public political conversation looks more like one over methods to reach a pre-agreed upon goal. These still happen, however often low value. But many people who need to have a political conversation want the other type: a cross-isle argument over objectives. Which are even more low value, and much more likely to end poorly.