Strange, I read it as exactly the opposite. Many times, people who are considered authorities in something, such as academics, have little or no real world experience in the matters that they're giving advice on. For example, why should a business owner take advice from an economist, who has never run a business (or even worked outside of academia), on how to run a business? By asking "what have you experienced that makes you believe what you do?", we can at least establish if someone really knows something or is just an "authority".

Similarly, if I see a book about software development, I'd like to know what significant software the author has delivered. If their expertise is mostly in writing books and making YouTube videos, I don't want to waste my time reading their advice.

Ironically, the author of this article seems to work for a "wealth management group", so we should ask what experience they have that would make them a credible source of advice in psychology or brain function. They write nothing about their own actual experience, only quoting various authorities.

GP isn't appealing to authority, he's suggesting a way to get to the heart of epistemological differences.