Another day, another distorted car analogy.
No, this is not like a car manufacturer charging for gas "passed through their nozzle".
Apple's app store has become a victim of its own success, in a way, because it has made the process of app distribution on their hardware so effortless for the end user that it is now widely assumed to be trivial.
It has also vastly simplified the process for the developer as well. I know I'm going to get flak for saying this from developers with short memories, but it is true. In the worst (hardest) case you were distributing boxes on store shelves containing stamped CDs - which you then had to support through other means. In the best (easiest) case you were distributing a shareware download on a website, and begging your users for purchases like a street performer with a hat on the sidewalk. Either way your profits were undercut by rampant software piracy. Let me emphasize that - _RAMPANT_ software piracy.
The benefits to Apple's app distribution channel - as well as in the way they control that channel - are not to be dismissed as a mere "nozzle".
Instead of a car analogy, I prefer to use one of a movie theater: The iPhone is a theatre, and your app is a movie that the user wants to see. Apple's app store is the doorway, the cash register, the security guard, and ticket taker at the head of the line. You - the developer - bring them your 'movie', and they hand you back a cut of the ticket sales. There are other movie theaters - like the Android one down the road - but when you bring them your 'movie', they give you back less money than you expected, because in addition to the front doors and the cash register, they also have a number of back doors, as well as a few tunnels under the property, and their security guard doesn't pay much - or any - attention to these.
I find this a much better analogy to understand some of the requirements of running a good app store. It also provides a different context for interpreting the case made in TFA, which in terms of the analogy is something like this:
Let's say the movie theater chain is also in the business of making movies. They put their own stuff up on the marquee next to yours, and since they are a big business with good revenue, they can spend a lot of money on these movies, and even sell tickets to see them for less than the cost of a regular ticket, because they are able to balance the books by counting profit from the concession stand, and their cut of the ticket sold for your movie, as well as their own movies. You couldn't call it abuse of a monopoly, because there is clearly no monopoly in movie theaters. In fact, the competing Android chain is massive compared to the Apple one, since they operate through franchise agreements. But in spite of this size difference, and the competition with Apple's own movies, you consistently get more revenue back from distributing your movie in the Apple theater. People don't mind going through the front door - because they're a different clientele, attracted by the cleanliness of the auditoriums, the unobtrusive security, the efficiency of the cash registers, and the consistently better quality of the movies they see, thanks in no small part to Apple's own self-financed movies that are ostensibly competing directly with yours.
So here's the interesting question: Are those movies competing directly with yours? Hard to say. If you believe that a community has a fixed amount of money they will spend on movies, and the competition is only over who claims the larger slice of that pie, then yes. If you believe that a community's spending on movies is influenced in large part by the quality of their previous movie-going experiences, then - not exactly. There are interesting issues of supply versus demand going on here. The worst outcome would be if Apple financed really crappy movies, and then drove away their patrons (and yours) by overselling them, decreasing the size of the movie-going audience.
An interesting situation? Yes. Stiff competition? Yes. Hard for a small- or big-time movie producer (software developer) to know the right move? Yes. ILLEGAL? Emphatically not. Apple could ban your movie from their theatre entirely - citing some inane decency rule they just made up - and it would still not be ILLEGAL. (The real Apple app store does this with pornography across the board, and they don't even have a competing product to "protect".)
Here's another analogy for further thought: Should Safeway be banned from selling "Safeway Select" brand pasta sauce, on the grounds that it is "unfair" to other pasta sauce makers that don't own their own store chain? Again, keep in mind that Safeway has far from a monopoly in supermarkets.