Americans vastly overestimate how deep their divisions are. It's actually pretty normal for countries to have real, viable separatist movements within them, and the US is nowhere near that. Quebec almost left Canada in 1995, Scotland almost left the UK in 2014, Germany was split into two separate countries for almost half of the 20th century, Korea is still two separate countries today, Catalan may or may not be part of Spain anymore (it's been a while since I checked), and nobody is even really sure how many Chinas there are. If anything, what's remarkable about the United States is how united you are, despite being a large group of people spread out over an entire continent. The vast majority of Americans speak the same language, follow the same religion, and -- perhaps most importantly -- identify first and foremost as "Americans". The fact that some of you vote for the "Have you ever hated the poor?" party and some of you vote for the "Have you ever hated the poor, on weed?" party is far less significant than the terminally online crowd would have you believe.
Importantly, the divisions are cultural rather than geographical. With the examples you list there's an existing border to trace with a bright red line whereas in the United States our divisions basically reflect electoral gerrymandering. Arizona exists as a state largely because Barry Goldwater strove to create a conservative paradise there. It's fair to say that the conservative demagogues we have in our south are attempting to repeat the process... but since they aren't starting with an uninhabited hellscape they're tripping over existing demography. You're right, however, that the Keyboard Kommandoes are definitely making much ado.