Earlier quoted context omitted.
To the people downvoting labster's comment: He's making a joke about left-handedness being referred to as "sinister" due to the Latin origins (apparently this may originate from how Romans wore their togas). He's not saying that teachers are making children any less evil.
Wait a minute, that doesn't sound right.
https://en.wiktionary.org/wiki/sinister#Latin
it shows a few definitions of "sinister" in Latin that seem contradictory. "left", "perverse/bad", but "auspicious" for Romans, while "inauspicious" for Greeks. And a Proto-Indo-European source which is positive.