"The issue is one of territoriality. Conservatives are territorial. They view the USA as their home and value it above other places in the world. They do all they can to protect the motherland and if that means screwing other nations, so be it. American interests come first, all others are tied for last.
In contrast, the liberal view is that we are one world, one people and whether you are here or there, black or white, straight or gay, American or non-American, it really makes little difference. They see the whole world as their home and so nationalism has little or no importance.
The American flag is a symbol of territoriality so it stands to reason that conservatives would cherish it more than the liberals. The liberals would prefer a single flag for planet Earth to replace all the flags of the various nations (and if that flag looked like the star of David, there would be little objection )."
Interesting take on things. Actually there are patriotic libs and conservs and there are libs and conservs that would overthrough the government if they could.
Socialists and communists get lumped in as libs and similarily the conservs get the kkk, freemen and the arian resistence types, neither of those extreme ends of the spectrum are very patriotic.
You are correct though that there are people that feel that they are a part of the human race more than a country, however having known several many with that attitude that's not a political view point of lib or conserv. Just as an example I've personally met different people that consider themselves worldings some that support and others that oppose capital punishment.
At any rate, you do touch on an interesting point. It is true that conservs tend to be much more ethnocentrical and largely indifferent to the rest of the world's welfare and prefer to lead by bullying.
It's also true the libs tend to have a clearer view of the importance of the world community and our role as an example of leadership to that community.