Why? Turns out, incivility ruins people's ability to think clearly and rationally:
"Uncivil comments not only polarized readers, but they often changed a participant's interpretation of the news story itself.
In the civil group, those who initially did or did not support the technology — whom we identified with preliminary survey questions — continued to feel the same way after reading the comments. Those exposed to rude comments, however, ended up with a much more polarized understanding of the risks connected with the technology.
Simply including an ad hominem attack in a reader comment was enough to make study participants think the downside of the reported technology was greater than they'd previously thought."
Food for thought...
(h/t to Jared Zimmerman)
--