What do you guys think about multiculturalism in the U.S.?

I think we should be careful not to embrace other cultures at the expense of our own. For example, it seems crazy that we say "happy holidays" instead of "Merry Christmas." Seriously though, if you go to China and demand that people start being more sensitive to your own religious views they will laugh at you and probably put you in prison for not worshiping the emperor. Anyways, we should accept people for who they are; but, like it or not, America is historically and still by majority a religiously Christian nation and it would be immoral to downplay this in order to appease other faiths. I think I'm just telling it like it is but give me your opinion.