Good question.
It seems to me like people who tend to identify as Republican, also tend to be stuck in very antagonistic mindsets.
For them, there’s always got to be an enemy. Everyone else is always out to get their stuff. Welfare for them is all about the government taking their money to give to all those wicked lazy people who covet their hard-and-honestly-earned money.
For them, the 9/11 attacks weren’t just about US involvement in colonialist corporate oil exploitation, and messing with their culture and lifestyle in their part of the world – no, for them it made sense that it was because “they hate our way of life”.
And as arch-right-wing TV inciter & (fake)-personality hate show host Glenn Beck said about all other countries’ support for the US second invasion of Iraq and the Orwellian “War on Terror” and “Axis of Evil”: “You’re either for us, or you’re against us.”
I think it has something to do with cultural origins in the twisted parts of Christianity, which is very deeply buried in frameworks of good vs evil, us vs. them.
Oh, and Republicans (especially ever since start circa 1968(?) of the party’s Southern Strategy to court racists) tend to think of people they don’t relate to as likely enemies (q.v. Blacks, Mexicans, Arabs, Russians, and… Chinese) – apparently it makes it easier to group-dehumanize them?
Could also have a bit to do with American military thinking. Our armed forces tend to look for who the plausible opponents might be in future for our more-expensive-than-all-the-rest-of-the-world’s-put-together military.
And, there is also some element of factuality, in looking at China as a large world power that does have a military that could compete with our own, and that too looks at the US as a potential adversary, particularly as regards, say, Taiwan. The government of China is pretty good at marking off the checklist of “bad guy regime” qualities, too:
* world-threatening ecological abuse
* corrupt totalitarian government
* the nasty kind of socialist state
* genocide
* severely controls its own people
* awful treatment of people who don’t go along, ethnic undesirables, Tibet, Hong Kong, etc.
* state censorship
* massive army and WMDs