Arrington is not technical. He's being sold on these things by slick guys in suits, with even slicker demos. He's good at evaluating new consumer products but there's no reason to assume that extends to evaluating new technologies. His lack of knowledge does make him extremely gullible.
I have a bridge in Brooklyn that I'd like to sell him ;).
You're absolutely right, he's just too gullible. I don't think he's taking money from these companies which products he's pushing but to someone else it might look that way.
ANY dev environment that requires you to download and install a runtime before you can run an app is bound for failure. Web apps will be impossible to beat... and they run on anything! You think you'll ever be able to run these RIA on a phone?! Not any time soon.