Well it is, as the string of argument is broken at (c) and (d), and with respect to the industry at question (flight training) (e) is also wrong. Since you don't need to have the adverts opposite an article, the pressure is not to write articles. Since advertising in this sector isn't contained in the main editorial section, and knowing the people who make the advertising at two companies in different sectors of this industry, I don't think the companies generally buy advertising around articles that they like.
This also shows that scameron cannot claim the expertise he does, as he has clearly shown he does not know this sector by using flawed arguments. He might have expertise elsewhere, and he might relate his expertise to, for example, avionics manufacturers, who may well advertise in the way he describes in the aviation press, but not to commercial flight training organisations.
Remember that the main market of these magazines (apart from Flight International, whos market is huge, and includes all sectors so the argument still applies) is club fliers, 95% of whom will never take any commercial flight training courses. Therefore the thrust of this argument which relates (I assume, in this forum) to the commercial side of flight training is drastically diluted. We are considering here edititorial independnce from the commercial flight training industry, not overall.