I wonder if he just doesn't have a good enough grasp of the English language to articulate his ideas well enough. I would go as far to say that no self-made billionaire is stupid.
Making money is far more about luck than skill. Always has been. Net worth is not a proxy for ability.
[edit] Don't get me wrong I'm not saying billionaires are idiots. I'm just saying that having a fat stack is not in and of itself a proxy for aptitude. Judge that on the person instead. Just judging them on their bank balance is an unnecessary appeal to authority that hasn't historically held.
Ma, a former English teacher, is one of China’s internet pioneers, building an e-commerce empire with Alibaba and a fintech giant with Ant.Stupid is a loaded word, but you can be a genius in chemistry and not be able to hold a "normal" conversation. You can also be homeless and super-smart.