Why isn't he behaving like a mature guy, 45 or how many years he has and not like a 10 years old kid. Just because he happens to be a billionaire?
Because that's the image he created, an eccentric billionaire. Don't be fooled by this image, Elon is in this for money. Not to save you, me, the planet or whatever else there is to save. Money. And currently he makes heaps of it.