I think we aren't as Christian as we once were because Christianity was once the 'norm' almost everywhere in America and those of us who embraced it were not attacked, insulted, and/or maligned, and nobody would have presumed to see it as a violation of anybody's rights.
We once celebrated Christmas and even Easter joyously and unoffensively pretty much everywhere--in the schools, in the workplace, on campus of our universities, in department stores, in the hospitals, in all government buildings, etc. It was a beautiful and satisfying component of the predominantly Christian American culture and even those who did not embrace Christianity enjoyed it as an American festival just as we would enjoy the cultural festivals celebrated in other countries including the non-Christian ones. The creche on the courthouse lawn was a charming American tradition that offended nobody and to sue somebody because it was there was unthinkable.
But with the rise of an intolerant Progressivism coupled with an opportunistic Libertarianism (capital "L") in which money could be made by challenging such customs and symbols, we have lost much of that. Our young are too often taught that Christianity is born of evil and corrupt influences or is a corruption of paganism, etc. etc. etc. and they never experience the joy and comfort that a relationship with the Christ brings to those of us who are blessed with that. "Merry or Blessed Christmas" has been replaced with a generic "Happy Holidays" in many if not most places. Christmas is no longer acknowledged in the schools that now have Winter Breaks instead of Christmas breaks. Public prayer is outlawed or not allowed in most public places. The school that includes too many old traditional Christmas carols in the winter concert can face severe retribution.
Christians are supposed to be sensitive and sympathetic to non-Christians whose feelings are of much more importance than any desire or feelings of the Christians.
And our country is definitely the poorer for it.