I agree, for the most part, however, with most 'pre-order' products, you are guaranteed your product before retail customers can drain the supply. FIFO.
For example, if I pre-order FIFA 2013 or any video game, I expect to get that game shipped or delivered to me on release day or waiting for me in the store for pick up, where they've saved my copy for me. I do not expect to be told that they oversold the pre-orders and I would have to wait for supplies to replenish while watching the 'johnny-come-latelys' walk in and out of the store with copies while I am tethered to some pre-order agreement, that limits my own options. Pre-orders are generally done to guaranatee product to those willing to commit early.
Maybe it is a case of more appropriate wording like 'pre-sale' instead of pre-order. Maybe they should have a presale for launches (5 million sales estimate...set aside 5 million phones for pre-sale...all else beyond that...pre-orders.)
That being said, I'm sure people are simply using this forum as a vehicle to rant and release frustration with people who share their frustration. I'm certain no one's world is falling apart because of the clumsy nature of this launch. I don't have a problem with that and am certain that aside from reading their posts, if you ran into them at lunch, you find them as normal as tthey generally are.
Obviously this isn't water or food...but it is $$$ and there's nothing wrong with being upset with not getting what you paid for when you expect it. Last time I checked, iPhone prices are not trivial enough to be aloof about and not inspire a little rage when not delivered reasonably.