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:

we still have freedom of speech and will keep having freedom of speech as long as there truly are Americans in our country. Merry Christmas everyone.
And yet another reason I won’t vote for Hillary Clinton! Donald J. Trump
6BULLSHIT
OBAMA the Muslim cancer invading America
Do it and say it anyway and fight for your rights.
Axelson Rian I am very much aware of that and never said anything about a National Religion. Did I?
violation of freedom of speech is right man, what the hell is wrong with you Obama, you are one of the worst presidents we have had in years man, you need to be impeached, get out!
He calls himself a Christian what a joke! Freedom
Speech Mr. Muslim!
All Christian soldiers stand strong
Merry Christams to all who served in our military!!!