It sounds like the author has mistaken the original advice of "Do what you love" as "Do what you think you love". How can this person know he "loves" being an entrepreneur when he never was one?

I guess he thought that being an entrepreneur meant more "If you build it, they will come", which is wrong. The reality of it is that creating a startup takes a lot of different skill sets, including knowing how to build a business and managing cash flow, etc. And just because you love the idea of being something doesn't mean you are actually good at doing it.