Patriotism, yes. Idolatry, no.
Father Jim Tucker posts some thoughts on flags on other symbols on his Dappled Things blog this morning. I post the following quote, with which I agree.
This is part of what I think is at the heart of this sort of exaggerated "outrage": In addition to the political questions and fears (which are understandable), there is a cultural problem of having sacralized the emblems of the Nation. To deface the American flag becomes an act of "desecration," to be criminalized by Constitutional amendment. To sing the Anthem in some other language becomes an affront to the holiness of that hymn and the sacred language of English. It's no coincidence that the great monuments in DC resemble temples, or that the statues to our great statesmen take on the aura of the effigies of saints. The pledge of allegiance, which I've written about before, just needs an "Amen" tacked on to make it complete. Caesar has basically deified himself again. People of faith, in particular, ought to be very, very uncomfortable with that kind of statist religiosity that turns patriotism, which is in itself a good thing, into something bordering on the idolatrous.
As Americans, we have much to be proud of culturally and politically. But it's good to remember that a great part of that American legacy is individual liberty, severe limits on government power, and a natural aversion to having to think, speak, or act homogeneously. All of which lead me not to worry much about foreign flags or other languages.