Your professor is right that it's not nice for any single party, including the NPS, to have overt control over a company. The same logic would apply to a chaebol having overt control too. The point isn't whether a prominent professor says something. It's whether the logic and data make sense. This guy's logic and data made sense to me. How is Korea supposed to create a new world class company like Apple, Amazon, Tesla, you-name-it if the chaebols manipulate and raid them before they have a chance to grow? Apple, Amazon, and Tesla all once were startups, but they were allowed to compete. Besides many other success stories.
If Korea is unable to replace an unprofitable chaebol with profitable companies through natural competition, Korea's people are less capable than I'd believe them to be. If a company is unprofitable and the government needs to prop it up, it is not a net positive for the economy. This is simple math, and I fear you are letting your emotions and political preferences prevent you from understanding that. Profitable competent companies are always better than unprofitable incompetent companies.