My username is a dead meme that is generally used to ironically mock oneself as stupid. Also, y is only sometimes a vowel for a reason; it's not the same open-mouth sort of sound as others. I think there's a big difference than that and marketing a serious security standard.
Fair enough. :) My real point, though, is that vowel transitions are inescapable in English, and so I don't think we ought to get overly worked up about them. And in fairness, this is just one more marketing langauge abuse on top of a giant heap of marketing language abuses -- OAuth is standing on the shoulders of giants here. How should a non-native speaker pronounce "Flickr" or "iOS" without any guidance?
(And we geeks have our own sins to atone for -- how to pronounce "/etc/", "/usr/bin", or "TTY" for that matter?)
On that last one, I'll share a quick story. I once worked with a genuine Unix greybeard on a remote project. He was tasked with debugging my terrible phone-home code, which was stored on a computer that I had couriered to him. The first time we ever spoke on the phone, he kept talking about "titties"... "this titty" and "the other titty". I'm sure that it was natural to him, but it took me a long moment before I realized he was talking about TTYs!
English is full of words that shift between vowels without a consonant. OAuth might be ugly, but it's hardly bending the rules of the language.