The Obama administration has directed the military to not allow personnel to say “Christmas”, in spite of the holiday’s status as a federally-recognized holiday.
The reason given by armed forces officials is that not everyone celebrates Christmas and that out of respect for them, military members should refer to Christmas celebrations simply as “holiday”-themed festivities.
This prohibition comes in the context of a wider push for political correctness in society in general and the military in particular, as evidenced by the recent reprimanding of Navy Chaplain Wes Modder for simply discussing religion, as chaplains are wont to do, with military personnel.
See how servicemen have reacted to not being allowed to say Christmas at the link below:

They will say it anyway. First Amendment, you who studied the Constitution…
Merry Christmas
Epic failure!!
What if an Islamic Suicide Bomber yelled Merry Christmas and didn’t explode?
Freedom of speech.
Robert, at the end our lives and of the times, every knee will bow and every tongue confess Jesus Christ is Lord.
Nobody does what Obama says anymore.He’s a washout.
And secdef and JCS all bow to Barry not in revolt, why???
Well how about we take the word ” PRESIDENT ” off of Obama?
Its called freedom of speech “Merry Christmas”