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:

Just found out this is boogus info.Xmas cards can still be sent.my statement about obama still stands.
God loves you mate, I have a BIG problem with it.
this is insane and why the military is going along with this proves to me he has everyone in place to start changing our cultures!!! the very same thing$#%&!@*started in Germany!!! and we know how that turned out!!!
Impeach idiot obama
He cannot give orders, and he can’t give that one in a Christian country.
Just get your what out of office.
I swear, OBama is a Marxist moslem.
Get him out of there already.he has destroyed our country enough we cant take another year
They have the RIGHT to say Merry Christmas no matter what your little pen writes who do you think you are
What happened to freedom to choose what we say,do, etc. So what if a non military person wishes a military person Merry Christmas and there dressed like a civilian then what?