The first few paragraphs of this article suggest the structure is not "here's a well-reasoned economic argument for why ad taxes are utile", but "I hate Google and similar companies, so we should screw them over with punitive targeted taxes".
Paul Romer has received the Nobel Memorial Prize in Economics. While that's just an appeal to authority, it still has more substance than dismissing a long post without even having read the majority of it. I encourage you to read the whole thing before concluding that there is no well-reasoned economic argument in this text.