I do believe that the USA is a special case. It would be difficult for me to provide sufficient justification for that statement at the moment, but life in the USA seems particularly complex in terms of the amount of brain power dedicated to scrutinizing language and other features of human behavior to determine familiarity, allegiance, and opposition. Communicating in English-speaking environments is, at once, stimulating and terrifying. My personal impression is that, because Americans are trained from an early age to observe a highly complex set of delicate constraints that become automatic for them, they expect everyone to have the same degree of sophistication, and will often react with outrage to anyone who fails to do so.

Essentially, because in some places Americans often talk amongst Americans, they sometimes attribute intent to what is simply a cultural difference. In those places, of which some subreddits are good examples, the rest of the English-speaking worlds will try to conform to American sensibilities.

The "hidden meaning" of expressions such "state's rights" is a problem for me, because, being a non-native speaker, I will often use expressions and phrasing that leads the reader to think I am defending some kind of hidden agenda that I myself know nothing about.

Those are just my guesses, though. I wouldn't write a post specifically about this because that requires real research. It's best for a real linguist or sociologist to comment on.

And oh, I forget about phatic expressions all the time! I often have to edit my comments to add words that will make me sound respectful and "a human". It's a little tiresome to me, not gonna lie. I wouldn't feel bad about someone not using those expressions when talking to me, but I must remember to use them myself all the time! :P