Are people less likely to express “dissenting views” on social media than in real-life, face-to-face situations, as the research claims? That seems unlikely to me. The Internet is notorious for inducing people to go “overboard” and say things they would not say face-to-face. So I suspect there is some sort of agenda behind this research.
The Internet, if anything, gives people the perfect platform to abuse others without remorse. Most people simply don't want to engage with anonymous people unless they can find common ground with them, but that's also the case in real life. The people who do want to engage with anonymous people (with no common ground) generally want to do so maliciously, and you are much less likely to face the consequences of your malice on the Internet.