For now.
A better analogy would be if Amazon suddenly refused to stock new Apple TVs and Rokus and Chromecasts in its warehouses and only stocked Fire TV devices, if we want to get all semantic about it.
> This whole uproar is about a single developer who had his app denied
There are multiple apps affected per the linked discussion.
> by a specific reviewer at Apple
No, by multiple reviewers on multiple occasions. Even appealing the decision results in the same response ("don't reference Pebble in your metadata").
> for a basic breach of their terms and conditions for putting Apps on the App Store
That's only being enforced for Pebble-related apps now that the Apple Watch has been released.
> The general consensus seems to be that a simple rewording (maybe not even having to remove the word 'Pebble') is all that he needs.
Apple's response (when SeaNav tried to appeal) was specifically to remove the word "Pebble". It's not a wording issue; it's an issue with that specific word existing in the metadata.
> Also, a theater buying a TV/Radio station and not allowing competing theaters to run ads is perfectly acceptable and realistic.
That's not what the more accurate scenario describes; you're still getting this backwards. It's the TV/Radio station buying/building a competing theater and preventing new ads from existing theaters that the corrected scenario describes.
> Just because one gets very large and popular doesn't suddenly mean the rules have to change for it.
Yes they do, per U.S. and European (at the very least; probably others are included) antitrust laws. Using one's market position to conspire to monopolize runs afoul of them.
And even if it weren't strictly illegal per se, it sure as hell doesn't mean that we should just lay back and let Apple do what it wants. What's the harm in calling them out on their dickery? A free market relies on an informed consumer base; such call-outs - at the very least - might put market forces in the consumers' favor for once.