Americans are well known for their ludicrously vicious sentencing policies ~ E.G. 999 years FFS ~ they know that no-one will ever serve that long so why even bother to pass such a sentence.
The Yanks agreed that this man should be tried under Scottish Law ~ tough titty you bigoted arseholes. Don't start complaining now.
Then of course there is the matter of whether he actually committed the crime and there does seem to be a large element of doubt over that no matter what the court in Holland felt. Take a look at the review conducted by the Scottish Criminal Cases Review Commission (all 800 pages and four years of investigation) has to say about it.
IMHO He was offered up by the Libyans as a sacrificial goat. I think those who are not blinded by having their heads so far up their own Yankee arses can see that.
Read:
http://www.lrb.co.uk/v29/n12/mile01_.html