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 can say whatever they want,f oboma
the only thing idiot can sign is trouble
Hey Obama you are a scumbag
The Evil one is out to destroy us and everything just wait till he puts the Muslim’s in place of top military spots and in control of ower nuclear weapons
What an idiot!
Guess the 1st amendment is under attack. This man is an empty suit. Sooner or later shot will hit the fan, so let the good times roll. Have MERRY CHRISTMAS and a HAPPY NEW YEAR.
Trump 2016
Say Merry Christmas any way.
Merry Christmas u he double tooth picks Obama
Kiss off