It is a fact that the US and British armies are stretched thin now. So the two governments are more or less forced to hire private security companies to take on jobs where personel protection is required.

I do not think these are to be confused with the term 'mercenary'

In the normal use of this word it means paying someone to fight for you. These are not (so far as we know) being used as front line troops. Yes they do have military training but then you do not want someone guarding you who has no idea of how to use a weapon or has no idea of how to handle potential threat situations.

There are security companies who take on the work of clearing land mines yet we never here them condemned. They too would use people with military training, albeit very specialist.

I would be more alarmed by the term 'civilian military advisors' such as those who were used in the Vietnam war.

A E Houseman wrote a good peice on Mercernaries;

Epitaph on an Army of Mercenaries

These, in the day when heaven was falling,
The hour when earth;s foundations fled,
Followed their mercenary calling
And took their wages and are dead.

Their shoulders held the sky suspended;
They stood, and earth's foundations stay;
What God abandoned, these defended,
And saved the sum of things for pay.

Still it does not get us away from the fact that these people are only required because our Governments stuffed up.