I have zero sympathy for developers in all of this. Apple has made it clear from day 1 that you are only permitted on iOS at their pleasure and that they can change the rules at any time. For those of you who were slow, the way Apple banned Adobe Flash CS5 apps right before CS5 was going to be released should have been a wake up call. Maybe you bet that your corner of the world wouldn't be interesting to Apple or maybe you didn't realize you could get caught in the crossfire of an unrelated Apple objective. Tough. This is what you signed up for. If you don't like it maybe you shouldn't have been developing iOS apps in the first place.
The people I do have sympathy for are users. They are not going to understand why some of their favorite applications and services on iOS stop being updated / eventually disappear altogether. Among other things, Apple sold devices using the availability of apps. I didn't see any fine print saying "your favorite apps might get rejected in the future" in those ads. And I can't think of a similar platform that might have given users those expectations. So users have a genuine beef. Developers are just not being honest with themselves about the consequences of their own choices.
People (users and developers) have a right not to be adversely affected by unfair competition.
Apple has a monopoly on selling iOS devices because of Copyright law - and that is how Copyright law is supposed to work. Apple develops iOS, and so aren't breaking any laws by making their App Store the default. Apple operates their App Store; selling access to the App Store under reasonable terms is also perfectly legitimate.
However, a particular sequence of actions can be illegal even though each of the individual actions that makes it up are legal. It is legal to ask someone nicely to stand in front of you (obviously they don't have to), and it is legal to move a knife and twist it in front of you; that doesn't mean it is legal to do the first then the second!
IANAL, but Apple's conduct around the 30% charge, while made up of individually legal actions, appears to be a straightforward breach of US anti-trust law. 15USCs14 (part of the Clayton Act) says that it is illegal to sell something on an agreement that someone won't purchase something else. So making developers agree that they can buy App Store services unless they don't buy payment processing for use within their app from anyone except Apple is not allowed in the United States, if the effect "may be to substantially lessen competition or tend to create a monopoly in any line of commerce".
Even if it wasn't illegal, it would still be wrong to try to lessen competition for their advantage, and it would be entirely appropriate for developers to criticise Apple heavily for it.
The people I do have sympathy for are users. They are not going to understand why some of their favorite applications and services on iOS stop being updated / eventually disappear altogether. Among other things, Apple sold devices using the availability of apps. I didn't see any fine print saying "your favorite apps might get rejected in the future" in those ads. And I can't think of a similar platform that might have given users those expectations. So users have a genuine beef. Developers are just not being honest with themselves about the consequences of their own choices.