Bias, mostly but not all left-leaning, has obstructed the free flow of dialogue. Unless the tech giants figure out how to remedy their tendency to mediate political discourse by leaning left, the bloom will fade from the unmatched flower of human connectivity, and bad things will follow.

In his 2003 fantasy film “Bruce Almighty,” funny man Jim Carrey plays a TV reporter who, following several personal misfortunes, has the gall to loudly second-guess God. Annoyed, the Creator lets his critic try his hand at directing the affairs of men. The newly omnipotent reporter discovers the dilemma of adjudicating humanity’s billions of competing petitions, and with rue and remorse begs the Almighty to take it all back.

The tech giants that unleashed the cacophony of global communications are similarly overwhelmed. As the number of social-media enthusiasts has exploded across our orb, so has a list of complaints from users who say their messages are electronically folded, bent, spindled or mutilated simply because of an offending turn of phrase.

Unlike a shadow, however, intolerance won’t disappear when someone turns on the light. Democracy, goes one marketing cliche, dies in darkness. It is only through honest and transparent engagement with a variety of opinions that someone can evaluate the relative merits of opposing views.

Social media is regarded as electronic bulletin boards where everyone is free to post his thoughts. Such thoughts are exempt ? for now ? from the requirements of the Communications Decency Act that apply to paper-and-ink publishers who are liable for the content of third-party users. If the gatekeepers of conversation continue to tilt left as arbiters of acceptable speech, they, too, are likely to be subject on one sad day to the government’s rules, and learn the perils of playing God online.