The crux of my belief boils down to this: an overwhelming majority of the time, when somebody posts, likes or shares something to social media, they are engaging in some form of virtue signaling. They are not interested in having their point of view challenged or about having counterpoints brought to their attention. All they care about is saying "Hey, look at me, I believe this thing, I'm a good person!".

A few adders: There are a lot of basic human interactions that are missing in social media: tone of voice, facial expressions, and body language. The threat of being punched in the face also doesn't exist in social media. In other words, a couple of motivations for putting true effort into being respectful towards the person you're talking to don't exist online.

Edit (17:30 CT 12-7-19): I am heading out for now, but I will be back later. I will try to respond to comments as I can in the meantime.

Edit (6:06 CT 12-8-19): Theres been a lot of good discussion on this and for that I'm grateful. A lot of you raised some really good points. Like the fact that social media opens the door for some people who might not have like minded people to talk to in their local community. Another being that the success you have largely depends on your goals, ie are you trying to convince the person you're talking to or your audience. Another good point I saw was that social media removes some barriers and allows for discussion of more taboo topics. As of now I'm not totally against social media, but I definitely think it has its advantages and disadvantages, just like talking face to face does.