But what also may be a significant factor is that most popular social media platforms are tuned to exacerbate contention, outrage, anger, hate, all the emotions most likely to keep a 'normal' person online and clicking for as many minutes of the day as possible. The last thing these behaviour modifiers do is promote the idea of slowing down and reading with care, and putting thought into replies, they are designed to promote rash and extreme responses.
There seems to me to be a grey area between what an individual can do to others through social media, and what social media does to an individual, and of course these will feed off of and into each other. There are some nasty positive feedback loops set up in most of the worst of social media, thanks to the underlying motives of those who use, own and profit from these types of social media.