Read his biography - the entire reason he has been able to achieve everything he has in life is because he doesn't have such a close-minded and pessimistic attitude. Rather than just letting the conventions of society dictate what he gets and does, he instinctively finds ways to work around them. While everyone else is busy checking the boxes expected of them, he's already moved on to the next level.
Some lessons are learned by doing things and dealing with the results. He hasn't been doing this long enough to see the long term consequences of any decisions he made while developing software at App Academy because those consequences haven't happened yet. Also, App Academy is a small company with about 10-20 people. Lots of things that aren't important with 10 people become very important on software projects with 100 people.
None of what I said means he isn't intelligent or talented. It doesn't mean he didn't do good work while at App Academy or that he won't do good work at AirBnB. It just means he's inexperienced. That's not a bad thing but it isn't something you can change overnight.
This guy was able to accomplish a ton in a year, acquiring the technical chops to get offers at top companies like Google. If he can do that in one year, imagine where he'll be in another year.
I would call it healthy skepticism.