I just posted this on Facebook. It is the first time I've put these thoughts down in words and I think has a role to play in the undermining of our country, so here we go:

But the fact that it is socially acceptable to export that behavior to 'real world' society, eg, to get people fired, etc, is where the friction is.

What you describe is definitely one aspect of the situation. I think another aspect, which I believe is why 'social media' is bad for society, if not humanity itself, is that it throws into close contact ideas and persons who would never have interacted, except through certain, structured, mediums.

For example, I could have Friend A who I interact in real life with and get along just great with who personally believes that rich people should be beheaded. Let's say I believe that rich people should rule the world. Since both of us would have views which we know are radical, we aren't likely to talk about them in polite company. In the old universe, if we were ever to interact, it would be through some kind of intentional effort or activity. Ie, I might read his book, or he might read my magazine, of we might go to an organized debate where we expect contradictory ideas to be aired. But now we are 'friends' on social media and we learn what we really think, and since we each view the other view as outrageous and perhaps even wicked, it becomes war.

In the old universe, when making friends, people gravitated towards people they were compatible with, and I don't think that is bad. In fact, I think that is healthy. It is of course also healthy to interact with people who have diverse viewpoints, but the medium by which that interaction occurs is important. Now there is no 'medium.' It is more than 'face-to-face.' It is flesh pressed upon flesh.

In my example above, I tried to pick some radically opposite viewpoints to contrast. It doesn't help, however, that some people find 'outrageous and perhaps even wicked' some really rather banal things, and on social media you suddenly discover (for example) that some 'friend' thinks you are evil because you wear a clip on tie instead of using the double windsor. Or, conversely, one of your 'friends' thinks skinning capitalists alive is a respectable, mainstream position, and is shocked to hear anyone opposed to skinning ANYONE alive.

Before social media, there was exchange of ideas. But they were often on web pages or on discussion forums. You had to go out of your way to find them, and make an intentional effort to participate. Now it happens just by scrolling through your timeline. Flesh against flesh, as it were.

Add to this what you described, and you've got a recipe for disaster.