Because he thinks the purpose of government is to subsidize and enable his every thought and let him do whatever he wants. Democracy gets in the way of that, so he prefers a corrupt government that isn't accountable to the people.
Also, destabilizing the US helps him with his business dealings with government actors in China, Saudi Arabia, and the like. And they can arbitrarily give him money and permits without popular support.
On top of that, he's narcissistic, impulsive, and thinks that he's saving the world (so anyone who gets in his way is anti-world).
Not the guy you want owning something like Twitter.