Laskern –
when you wrote: – Tosfas in Baba Metzia 59:2 starts לא בשמים הוא, can be explained that the Bas Kol revealed that what it says אחרי רבים להטעות, we go after the majority, which can mean either in quantity or quality , is in quantity.
Perhaps you meant אחרי רבים להטות ….. even though the רבים occasionally is wrong also,