This is why phrases like "we should nuke them from orbit", which might be calls to violence if made by a head of state, are generally seen as satire, because there's no chance of me actually nuking someone from orbit. Context matters.
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.