We do so because in a diverse society, efforts to restrict speech can become a tool to silence critics, or oppress minorities.
Because on your fast day you see to your business and oppress all your laborers!
Hamas claims to be fighting for freedom while invoking laws that oppress women and religious minorities.
mid-14c., from Old French opresser "oppress, afflict; torment, smother" (13c.), from Medieval Latin oppressare, frequentative of Latin opprimere "press against, press together, press down;" figuratively "crush, put down, subdue, prosecute relentlessly" (in Late Latin "to rape"), from ob "against" (see ob-) + premere "to press, push" (see press (v.1)).
It is the due [external] restraint and not the moderation of rulers that constitutes a state of liberty; as the power to oppress, though never exercised, does a state of slavery. [St. George Tucker, "View of the Constitution of the United States," 1803]Related: Oppressed; oppressing.