Of course Americans cherish cultural diversity, but without a common ideological framework which is conducive to tolerance and the democratic process, our nation's foundation will collapse. Excessive multiculturalism doesn't work. Of course we need diversity, but allowing citizens to subvert the democratic process and equal application of the law to suit their own cultural background (like the use of Sharia law in marital disputes for example) is utterly ridiculous.
Despite my other advocates for American to rapidly decentralize (though doing so is for economic, representative, and political reasons). In general (with the exception of nations in the same position as the United States). I find it a general virtue to promote a singular, national set of common values, cultural traditions, adornment of famous figures, and championing of the national history. This is for the simple fact that doing so creates not only a unified populace, but one that is not balkanized and one that can relate to each other and rely on each other. Its human nature to prefer the person/group with something in common to you, therefore, it is best to capitalize on this aspect of human nature to promote a degree of unity that may save many nations from total social collapse when times get tough.
People should still have the freedom to practice their own culture/sub-culture, but it should be encouraged to promote common characteristics and unifying factors among them all.
From the majority point of view it would be very convenient to have a unified national identity and make other values parts of the national fringe. However, this hurts minority opinions. Yes, a national identity might make most people feel better, but it would alienate other groups.
Consider a country like Pakistan where the majority of people might actually support an Islamic theocracy. If a unified national identity was created there, imagine what would happen to non-Muslim Pakistanis. Some may argue that in America the chaos that might result from multiculturalism outweighs the downsides of minorities being alienated because Americans are generally quite tolerant. However, with the numerous divisions in ideology, religion, and race found in the us, promoting a single image of the ideal American is likely to create conflict.
Multiculturalism only scares those who have something to lose with more diversity. Give minority groups the freedom to believe what they want to.
Encouraging conformity will not only destabalize the nation in the short term but it will also make it more oppressive towards minorities in the long term. Once the line has been drawn between "us" and "them", it will be easier for extremist groups to start blaming the non-conformists for all of the nations issues. We see this happen time and again throughout history where a minority group which is not represented or included by the state ends up being attacked. It also makes progress far more difficult as any view that does not conform will be eliminated simply for not being traditional.
It's not sustainable. It's extremely exclusionary. It only breeds Nationalistic hate. There's really no other thing to say and no good reasons I can think of because the entire value of a lack of centralized morals is that all morals are at least scrutinized equally preventing tyranny of the majority.
This may cause a majority of people to be overly-proud of their nation. This can lead people to support their country no matter what is right or wrong - they will be so caught up in pride and "love" for their nation they will blindly think everything it [their nation] does can be justified. Many people support America in the war in Iraq, just because they themselves are American; when if they knew that over 200000 innocent Iraqi citizens have died since the war began. Nazi Germany had a nationalist movement similar mentioned to the one listed above, and look at what happened - millions of innocent people died, and the majority of Germans didn't bat an eye over it all (not while it was happening, that is).
The foundation of this nation is predicated on the individual. Any attempt to minimize, or "collectivize", the individual should be rejected.
This would be yet another victory for the leftists who seek to abolish individualism. This would be another "incremental" step in the erotion of the status of the individual.