Idk, the particular flavor of outrage varies greatly depending on the platform. 4chan, Facebook, Twitter, Pinterest, YouTube, all of the them are drastically different platforms with cultures that emergently form from early design decisions like anonymity, One-to-many vs many-to-many communication paradigms, thread layouts, and moderation decisions.

How do you figure the '50s? Times we've been more united than we are right now seem more the exception than the norm, to me, since the founding of the country. Hell we haven't even had an elected member of the Federal government kill or attempt to kill someone over a political dispute in a while.

My sense is that lots of divided people (mainly fringe) have basically been silenced for years. Twitter has made it possible for those people to have a voice and more problematic made it super easy for malicious actors to mimic those people's ideas to make the situation worse than it really is.

My (probably unpopular) opinion is that they simply shouldn't have a voice. Twitter is bad for society period.

I think this misses the point. The division isn't within the government; it's between individuals.

And I don't think the power of short messages is specific to the United States

Where did I talk about the government?