This is one of the reasons exit tax has failed miserably around the world: it prevented good business people doing business in punitive countries in the first place.
You have to define the "good" in "good business people". If you are a global scale entrepreneur planning to start a business and looking for country with an educated workforce that has good infrastructure but you need to be able to take your gathered wealth when the business is mature (read you have an obscene amount of wealth) in order to find cheaper less educated workforce to keep up operations in order to generate more wealth for yourself. Then you are a "good" businessman only in the sense that you are good at maximizing your own pile of gold. Morally you are bankrupt. So what does a "punitive" country loose by not letting you reap the benefits of a "high taxes system" for your own personal gains?
What should he do, not sleep at night thinking about "the good of the company" to be a "good employee"?!
That's not what the article is talking about.
I think the point that exit-tax proponents are attempting to make is that the current social understanding of wealth is that wealth-holders tend to show that they are capable of efficiently allocating resources, so they should be able to continue to do so while they're still in the country, thus we tax them lower than we would if we could more efficiently use those resources. So think of it like a partial taxation or a conditional subsidy alongside a future promise of additional, likely greater, taxation from their future business dealings, job creations, &c.
Since they're leaving, the country is losing out any investment it assumed at an earlier date when deciding to tax less, so the country would effectively just be reclaiming a conditional subsidy.