Those are the Hebrews/Jews, the conversation is about the Gentiles who had no way of knowing, unless they came in contact with the Hebrews and learned from them, as some did.
But the rest of the Gentile world didn't know, and God did not pass them by who He knew would believe.
Someone will say that I'm adding to Scripture what is not there. Im not stating a fact in Scripture because it's not there, I'm stating what I believe.
I believe there many saved in Egypt when the 10 plagues took place and some of the Egyptians with no knowledge of a coming Christ believed what they saw in the power of Jehovah God and believed He was the one and only God.
I think they repented and acknowledged God and were saved. the reason many of them gave them gold, silver, costly apparel, livestock when they left.