Stupidity would not be totally stupid if it did not go in terror of intelligence. Vice would not be entirely vicious if it did not hate virtue.

[La sottise ne serait pas tout-à-fait la sottise, si elle ne craignait pas l’esprit. Le vice ne serait pas tout-à-fait le vice, s’il ne haïssait pas la vertu.]

Nicolas Chamfort (1741-1794) French writer, epigrammist (b. Nicolas-Sébastien Roch)

Products of Perfected Civilization [Produits de la Civilisation Perfectionée], Part 1 “Maxims and Thoughts [Maximes et Pensées],” ch. 2, ¶ 139 (1795) [tr. Merwin (1969)]
    (Source)

(Source (French)). Alternate translations:

Stupidity would not be absolute stupidity did it not fear intelligence. Vice would not be absolute vice did it not hate virtue.
[tr. Hutchinson (1902), "The Cynic's Breviary"]

Folly would not be altogether folly if it were not afraid of wit. Vice; would not be altogether vice if it did not hate virtue.
[tr. Mathers (1926)]