Two types.
blacks and whites.
In the Army, you are always moving and always away from family. With the masons, you show up to a new place and have instant family. It used to be the Army was your family, but with so many married, young soldiers, they treat the Army like a 9-5. The abysmal leadership that exists in the field grade ranks does nothing to improve that. Hence, the masons.
The white type masons (hate to break it down by race, but that is the reality) have an OLD tradition in the US Army and the British Army (from whom we take most of our traditions) old George Washington. Think it is a coincidence the back of the $1 bill has the masonic all-seeing eye?
Went to a luncheon where the guest speaker was a retired 4 star and 33 degree mason (both the highest ranks in the Army and Masonry) coincidence? I don't think so.
Oh, and I am not a Mason.
In summary,
On the black side, instant family (From my experience blacks have a very strong tie to family and the seperation would appear to strengthen the desire to have masonic ties)
On the white officer side, tradition and possibility of high rank through favortism.
On the white enlisted side, you don't see a lot of masons.
My two cents