IMO Elon Musk is rational and also expressive. He thinks from first principles (aka how does the world really work?) and he communicates that way.
Most people can't handle that. They can't handle when someone is expressive (aka the Tesla @ 420 tweet, he simply expresses his opinion) or reasoning from first principles (weed is legal right? Yea, might smoke it, might not, does it matter? New experience is new data, hmm, doesn't seem too interesting).
They think he's insane. He isn't. He does live a bit in a bubble where he sometimes forgets that other people are judgmental, mostly in a conservative sense (compared to how he thinks). But those judgmental people don't see one thing: the guy is hunting for truth, finding it and he applies it to its product.
Nothing beats truth* (the fact that we're using computers now and not an abacus is evidence of that)
* All the standard considerations of science apply (falsification, learning from your mistakes and so on).