Whether this is true or not is debatable. But the article Crude Comments and Concern: Online Incivility's Effect on Risk Perceptions of Emerging Technologies by Ashley A. Anderson, et. al., gives some evidence that supports the converse.
From the abstract:
Uncivil discourse is a growing concern in American rhetoric, and this trend has expanded beyond traditional media to online sources, such as audience comments. Using an experiment given to a sample representative of the U.S. population, we examine the effects online incivility on perceptions toward a particular issue—namely, an emerging technology, nanotechnology. We found that exposure to uncivil blog comments can polarize risk perceptions of nanotechnology along the lines of religiosity and issue support. [Emphasis added.]And, from the conclusion:
The effects of online, user-to-user incivility on perceptions towards emerging technologies may prove especially troublesome for science experts and communicators that rely on public acceptance of their information. The effects of online incivility may be even stronger for more well-known and contentious science issues such as the evolution vs. intelligent design debate or climate change. Future research may explore these issues to gain a better understanding of the formation of risk perceptions for controversial political or science topics in the context of user-generated online comments. [Emphasis added.]Obviously, if my goal is to learn -- to change my mind or understanding about a topic, such as climate change for example -- then becoming polarized on issues about the topic is a bad thing. Those readers with the same goal will agree. And those with other goals? I don't care too much about them.