Everyone has opinions that would get them cancelled on Twitter. Most of us are sensible enough to keep them to ourselves, or, at least, off Twitter, without even having the responsibility to maintain the image of a business. He has a duty to his employees, his clients, and his investors that goes far beyond the standard duty of "Don't be an asshole on Twitter."
Political hyperbole is also kind of the norm on Twitter (which is one of many reasons I don't spend much time there), so it's entirely possible he thought he was being humorous, and that it was abundantly obvious that he shouldn't be taken literally. Which might even be true. But CEOs are at extra risk of getting taken out of context and willfully misinterpreted, and they should fucking Tweet like it.
I disagree with what he said, but I'm more insulted that the people are allowed such insane levels of power and responsibility and are given such disproportionate compensation have the common sense of a middle-schooler.