by Natalie Wolchover and Live Science tries to answer that question. Even though the article itself is 5 years old, I think the article still holds up after all this time.
I kid you not in a direct quote from the piece
With a presidential campaign, health care and the gun control debate in the news these days, one can’t help getting sucked into the flame wars that are Internet comment threads. But psychologists say this addictive form of vitriolic back and forth should be avoided — or simply censored by online media outlets — because it actually damages society and mental health.
Doesn’t that sounds like that observation was made recently?
Although the article does make a good point that anger does lead to even more anger LINK