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:

Illegal order and under USMJ must not be obeyed
MERRY CHRISTMAS MR. OBAMA!!! YOU are a MEAN HEARTLESS PRESIDENT , MR. GRINCH!!!!!!!!!!
Now he is telling what us what to say! I thought we had freedom of speech yet. Merry Christmas everyone.
P.O.T.U.S now means piece of totally useless s..t
Maybe the President is the anti-Christ!
Freedom of speech is being violated again. The people who voted for him should be ashamed of themselves.
Impeach him NOW!!!
The Prince of Darkness is in control of him.
Fool
merry christmas to all you Muslims