Then it is the opinion of every published Hebrew grammar and everyone who can read and write in Classical Hebrew. 'Ayin is a voiced glottal stop.
It is not a vowel. To call it a vowel in this context is categorically, unequivocally false. It does not appear in the Tetragrammaton. (The only letters present there are yod, he [x2], and waw/vav). These statements are all verifiable, fundamental facts. Why do you deny fact in order to prop up such obvious fiction? What merit is fiction here? What can this fiction give you that is lacking in these facts?