Because nations and their leaders are different to people.

When Britain declared war on Germany in WW2 were they ‘threatening violence’ and would that get them banned from Twitter?

Instead of a hypothetical you can just use the example from the article:

> Twitter said it would not ban President Trump despite incendiary tweets, including allegations that he threatened to declare war on North Korea.

Right, but using the example of Britain and Germany back in WW2 removes it from current politics and allows us to think of an example of a clear and direct incitation of violence that almost everyone thinks was legal and morally just and would have been appropriate to Tweet.

Threatening to declare war is a diplomatic tactic. Just because Donald Trump did it doesn't change tactics used by world leaders.

I don't recall any nukes dropping, or armies being deployed--but if you listened to the media around that time, it was 10 seconds to midnight. What we actually did see is people holding hands and crossing borders. Yet still, even today, we hear about the threat of war.

It is not wise to piss off world leaders if you have to travel the world. So the high ranking executives tread carefully

Not trying to be glib, but it makes money for twitter. Trump has been absolutely amazing for Twitter as a business.

I see this assertion thrown around a lot, but is there any evidence of that or is it just one of those "obvious" things?

Senior Twitter PM told me.

Yes, not enraging millions of people will tend to help a company's bottom line.

No, the engagement from the outrage drives revenue.

Fear and outrage is a major component of driving traffic to news itself, no?

Because there's a public interest in hearing what (say) POTUS has to say.

Twitter wouldn't be anywhere near as relevant without world leaders, and by world leaders, we really mean the shitposter-in-chief. A sizable fraction of their engagement over the past four years is directly attributable there, and the second and third order effects are ridiculous.

Twitter's moderation and content policies are such a mess that it is quite possible to get away with spewing hate and violence with impunity, or to get banned for the most anodyne and innocuous remarks. It's entirely reactive and arbitrary.

Average people don't care or use Twitter, the newspapers just tell them in whatever bias way what they wrote. Twitter is nothing without high profile users, especially the main clown. Twitter is used by shulls, activists and media people. The tech crowd is minority.