Everyone is applauding this because they hate Trump, but take a step back and see the bigger picture. This could backfire in serious ways, and it plays to Trump's base's narrative that the mainstream media and tech giants are colluding to silence conservatives (and maybe there could even be some truth to that.) I know the Valley is an echo chamber, so obviously no one is going to ever realize this.
EDIT: Scroll down a bit, the original poster made their account private a few moments ago
> Glorification of violence policy
...
> You may not threaten violence against an individual or a group of people. We also prohibit the glorification of violence.
(https://help.twitter.com/en/rules-and-policies/glorification...)
But whichever way they interpret it, all that really matters when it comes to fairness is that they are consistent.
If we look at a very non-hypothetical person named Donald Trump, he wrote "when the looting starts, the shooting starts" immediately after "I won't let that happen" and "the Military" and "we will assume control". Without context, the words could be just an opinion or observation, but in the context he used them, that's not a reasonable interpretation. You don't mention sending in the military (who have guns, obviously) and then mention shooting as a total non sequitur in the next sentence.
If somehow improbably he meant it to be an opinion or observation, he phrased it terribly, and Twitter is within their rights to interpret it how he wrote it.