If you stand back and look at this rationally boys, the truth is that it SHOULD be a very good way of building bridges between raw recruits and instructors in Castel-Bordel. That assumes of course that the would be fut fut has a single gram of compassion in him - which never appears to be the case.
The horrible truth (as Murph suggested in his God talk above) is that their sudden transformation from being a lump of dog turd (as are all raw recruits) to a being somebody with authority simply goes to their head.
It's a very sad sight to behold...
However the joy of being able to take the bitch around the back of the foyer and knock the crap out of her at a later date somehow makes the initial suffering worthwhile in my humble opinion. When you do get posted to your regiment, and are kneeling at your bed praying (as all legionnaires do of course) during a moment of severe depression when you have no more beer for example, it does give you something to actually focus your prayer on - "Please, please God, send that bitch here soon".
So - if they were out - and now they are coming back, is it safe to assume that the BPLE send them on a Motivational Training course before unleashing them - such as a quick tour of duty in the swamps on a "Thunderbirds are GO!" Zodiac in the 3eme for example - (and those that survive the spiders win a year back in the 4eme) ?.
Just an idea of course...