It feels like Hillary's advisor was merely watching French TV and transcribing what journalists and politicians said publicly. The mention of Bernard Henri-Levy proves it. When you sum up a geopolitical situation in a few sentence, you don't waste any explaining BHL is a "semi-joke", unless your own knowledge is cursory.
With regards to the French population, you have to put it in context (April 2011, see https://en.wikipedia.org/wiki/Timeline_of_the_Arab_Spring ). The Arab Spring was still going "smoothly" elsewhere, and we were all watching Egypt, Tunisia, Morocco, Syria and Algeria where things were handled "more or less peacefully" back then, at least to the French eye. Qadaffi's repression, on the other hand, was violent from the get-go.
It was a perfect storm (1) for Sarkozy, as on top of the things mentioned in the cable, he had to prove that he was serious with his Mediterranean Union, and more importantly he had to disprove the allegations that Qadaffi financed his election.
Wether it was the right thing to do or not, I personally have no idea, but it was pretty much a no-brainer at the time for France to distance itself from Qadaffi during his civil war, and fuel the opposition.
(1): unrelated, but maybe I should have said "homerun" in this case? My English fails me.