I just finished http://en.wikipedia.org/wiki/Candide

Great book, I got the Peter Constantine translation. It was published 30 years before the French revolution.

To answer your question, the fact that the powers that be at the time took the trouble to ban the book is some indication as to the potential they felt it had for disruption.

If you want a behavioral explanation, you should consider the morale of any kind of resistance. Such morale depends on some kind of foundation and support. Inspiration for these may be found in art.