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:

Someone is going to roast.
Merry Christmas ya’ll!!!
Peggy Taylor, 1 bullet … ONLY 1 bullet …..
Say what?
If you can’t say Merry Christmas, then cancel it as a federal holiday.
Does he act like someone who would order US troops to bomb ISIS
You must be smoking the same stuff the reindeer get..
What we need is a world wide revolution.
Merry CHRISTmas!!!
Sorry Obama we are a free country home of the brave , you won’t beat us American people or will you mind control us be ready to have another fight a fight we will win WIN OBAMA