I understand the permissibility of Meat of AhlalKitaab; however, the religion of the "blade or machine" cannot be known hence doesn't that
become impermissible?

The principle in the meat slaughtered by the people of the Book [Ahl al-Kitab] is permissibility. Based on this, it is permissible for a Muslim to eat from this meat so long as it is not certain whether or not the animal was slaughtered in the first place or whether the person slaughtered it was from among the people of the Book.