Because the whole point of the exercise is to show how standards-compliant, open, web apps work so great on iPhone OS. Except by excluding every browser but Safari, it may as well be a front for the App Store. It might be standards-compliant, but it sure as heck isn't open or inclusive. In that regard, even Flash runs in more browsers than this showcase does.
Instead, as far as I can tell, the primary point is to promote Safari and prove that Flash is unneeded to make pretty neat graphics/interactive thingums.
Opera is maybe justified in being miffed if Apple can get traction off the back of using “open” and “HTML5” as buzzwords, but I really don’t think the primary audience for this showcase knows or cares much one way or the other what HTML5 really means.
Just sayin.
("Opera for the iPhone" is using a mediator service, and as such is not a real web browser).
> The demos below show how Apple’s Safari web browser supports the capabilities of web standards such as HTML5, CSS3, and JavaScript.
Gruber’s point is this: if Opera wants some better “HTML5” demos (presumably that work across browsers, and don’t just “use HTML5 as a buzzword”) they can easily make some themselves. Why should Apple be responsible for making sure their Safari promotion showcase works perfectly in every other browser?
As for why they block other browsers: probably some or most of the demos break in some way or another. If a naive user with (say) Firefox visited a page and the layout looked like shit and nothing worked, the user would quite reasonably think that Apple’s site was broken.