Respectable conservatives allow liberals to be loyal only to the left, and to claim to be patriotic. Respectable conservatives are always saying how patriotic their liberal opponents are. So when leftists wave the American flag it is absolutely meaningless, and conservatives are always grovelingly grateful to them for making even this token gesture.
Liberal patriotism is a wooden nickel, and conservatives gobble it up.
Liberals, however, will not accept such fake currency when a symbol is important to them. Likewise, when Mexican music was played and the first all-Spanish speech was spoken at the Republican Convention, it was not a meaningless token like Democrats waving the American flag. The media said over and over that they didn't want to be betrayed by Bush. It means no more talk of protecting the US borders. It means no more English-only initiatives.