No Hostility to Christianity?

So there's no hostility toward Christianity in America today, huh? From Lifesite.net:

The United States Supreme Court yesterday decided not to review a case challenging the constitutionality of a New York City public school policy that expressly permits the display of the Jewish menorah and Islamic star and crescent during their respective religious holidays, but completely bans the display of Nativity scenes during Christmas.

Could there possibly be a valid explanation for allowing Jewish and Islamic religious displays (which I'm perfectly fine with, the way) but refusing a Christian display?

Actually, yes. It's called hostility toward Christianity. It's become vogue for our society to diminish and deny any public expression of Christianity, the religion of the people who founded the United States, the religion upon which our government is based, the religion which gave our society its traditional flavor. Christianity, now banished from public acknowledgment.