Before you buy totally into the whole military suicide narrative:
A few things to consider:
1. Apart from the military, suicides are vastly more common among males than females (and the military, especially Army and the Marines, are heavily male).
2. Apart from the military, suicides are much more common among younger people (and the military is weighted toward youth).
3. Apart from the military, suicides are much more common among unmarried people (and the military is weighted toward singlehood).
4. Apart from the military, suicides are much more common among people living far from their families (and military people invriably live far from their roots....).
Combat-related stress is a factor, but it certainly is not the only factor in high suicide rates among troops. Rather than a comparison to the civilian rates, it would be better to compare rates to the situation pre-9/11.