The First Amendment provides and protects our right to free speech. What it does NOT do is excuse us from the CONSEQUENCES of exercising that right. You know the story about yelling "Fire!" in a crowded theater where there is no fire. That's free speech. Being arrested and tried for doing so are the consequences of exercising one's free speech rights.
The fact is that rights are a two-way street. It's kind of like Newton's 3rd law of gravity: For every action, there is an equal and opposite reaction.
Tweeting “I’m going to destroy America,” is absolutely crying “Fire!” in a crowded theatre - as those two learned to their detriment. If you read the comments following the article, you will see that their fellow citizens agree with US!
No right is absolute.
Your “Fire” comparison is not anywhere close to being correct or sufficiently adequate to support your approval of government control over a ‘tweet’. I am glad you are not my attorney.