Oomis: I would be reluctant to accuse the Steipler of not being objective if I were you. He acknowledges the differences, but writes that some aspects of Sefardi havara are also certainly incorrect. A Patach and Kamatz should not sound the same and neither should a Tav and Sav (with and w/o a dot).
How do you know that the Sefardim came “first” are more “authentic” are the “prime source” and are the “original speakers of the Hebrew language”? Aren’t we all descended from Avraham Avinu?