I say this not to imply that Trump didn't know that this statement could be taken in multiple ways, but to remind people that even if it can it doesn't matter. It's tragic this has happened, and also tragic to have a leader who reacts to the situation in this way, and that a large swath of the country applauds him for it.
Vague and menacing threats are much more thuggish behavior than emotional reaction to the killing of an unarmed civilian.
As for what Twitter is doing, I'm curious whether they follow this path to it's logical conclusion, which is, eventually Trump being banned from Twitter. He's a huge driver of traffic for them, but perhaps they're thinking about life after Trump at this point, months away from the election.