Why does that cause difficulty?  Christmas is specific to a single religion, Halloween, while perhaps having some Christian origins, is not.  Christmas has its origins in paganism or such, if I recall correctly, and its pretty well established that Christ wasn't born in December.

You would, I think, have a problem if your local schools put on a Ramadan or Kwanzaa or Hannukah play, would you not?  Particularly if the play, pageant, or concert had content specific to that religion?

There is no war against Christmas.  The whole thing is overblown by Christians who are bent out of shape by being greeted at the mall by "Happy Holidays" instead of "Merry Christmas".  I always thought that sharing was one of the basic fundamentals of Christianity, yet it seems that many Christians don't want to share the "Holiday Season" with the Jews and folks who observe Kwanzaa, along with the myriad of other lesser known holidays and festivals observed by other lesser known religions.