It's fascinating. This is the way I look at them, as being on the side of people who agree with Apple on this one.
#1: Don't agree. Apple has 180,000 apps in their App store, maybe a good time to remove incentives for a new influx of non-programmer-written apps straight from Flash? Oh, they're getting rid of other stuff that also encourages people to use other tools than their own? I think they can live with that.
#2: They're not. Tell me where and when Apple said: "You will be able to develop for the iPhone using any and all tools of your choosing." They didn't. They're simply clarifying what's been their position all along, that XCode/Cocoa is the environment in which you create iPhone apps. Sure, other stuff have been able to sneak in stuff, but hardly with an Apple seal of approval. If you're using one of those tools without a suspicion Apple might not like it even before this, I'd say you're a bit naive.
#3: Irrelevant. Apple has told developers which tools they can use from the get-go. I imagine the existing cross-platform products have been too small to have been a priority, but here comes Adobe with something that creates iPhone apps straight from the desk of a designer. Yes, did you see the CS5 presentation? "Create iPhone apps without writing any code!" Sounds like great apps to me.
#4: Of course it's unfair. But there isn't any better way to enforce their rules. Naturally there'll be apps that fall through the cracks. But a "Aw, why can't I when that app could?" whine sounds very 7-year-old to me. They're putting up rules, if you follow them you should be fine. If someone does something that might be within the rules, but they're not sure, they might get rejected. If someone else tries the same thing, they might get rejected, regardless of whether the first guy was caught or not.
#5: Not sure this ia a very good argument either. For me, I develop for Apple products because I love the platform, and I think there are quite a lot of other apps that have been hanging around with Apple because we feel that is the best platform in the world. Not perfect, but best. And I like it when Apple says that what we've learned during the years of sticking by the company because of that conviction, rather than some sense of duty, is going to pay off. Sure, Apple could release the platform to any and all languages out there, implement C#, Java and whatever else might be popular right now. But that would seem to me to cater to the populist crowd, rather than the faithful, so to speak. And those programmers are the same programmers that will move away from the platform when something else catches their fancy. I think Apple wants people like Omni Group rather than the "Oh, lord, another device, another language, who cares? I guess I'll _have_ to learn it, then."-crowd.