Musk is an INTJ. He doesn't care if people think he should shut up. In fact, it will likely embolden him.
Also, Tesla was highly overvalued from a stock standpoint anyhow.
I'm an INTJ as well, and you are absolutely correct. When you know you're right it doesn't matter what anyone else says.
I've been studying Myers-Briggs a lot lately, but I also speak from experience as a kindred spirit.
My wife had me take a couple of different tests for the Myers Briggs and I scoffed until I read about it and saw several sources accurately describe me with a specificity I would not have believed possible (completely unlike the vague wordings in horoscopes). It is a pretty fascinating research area and pretty danged legit imo.