I know the PR person at Robbins they just published this:
Robins Air Force Base
Air Force Statement on “Have a Blessed Day” greeting
We are a professional organization defended by a professional force. Our defenders portray a professional image that represents a base all of Middle Georgia can be proud of.
78th Security Forces members have been asked to use the standard phrase “Welcome to Team Robins” in their greeting and can add various follow-on greetings as long as they remain courteous and professional.
The Air Force takes any expressed concern over religious freedom very seriously. Upon further review and consultation, the Air Force determined use of the phrase “have a blessed day” as a greeting is consistent with Air Force standards and is not in violation of Air Force Instructions.
Someone has some common sense at this base.