Who played god and decided that these sounds were identical "uh"s? And for which region are these pronunciations valid?

You'd have to ask Mr Garg, and he does not read this board postings. But, my guess is he either adapted it from some dictionary or kind of made it up on his own. The IPA evokes such negative responses from most people, that most popular words folks fall back upon faulty transcriptions methods. and systems.

Ceci n'est pas un seing.