Are they all guilty ?...What about the part of the verse that talks about or excusing regarding their conscience ?.....Christianty did not reach America untill the 16th century. Before that the Indians had no chance of hearing about Jesus Christ . How was they saved ?
Everyone who has ever lived anywhere... Guilty. We are all guilty of sin.
"for all have sinned and fall short of the glory of God," (Romans 3:23)
Only those thay God chose before the foundation of the world, "the elect", will be saved. And they are a very few.
The vast majority of people who have ever lived will be in hell.
"Enter through the narrow gate; for the gate is wide and the way is broad that leads to destruction, and there are many who enter through it. For the gate is small and the way is narrow that leads to life, and there are few who find it." (Mathew 7:13-14)
How can a guilty sinner escape judgment unless he has given his allegiance completely to Christ who paid his penalty? Otherwise he has a penalty to face that there is no escaping.
But I see a slight chance for a very few people who never knew Christ to have been saved... if they searched for God with all their heart:
"You will seek Me and find Me when you search for Me with all your heart." (Jeremiah 29:13)
&
"For He says to Moses, "I will have mercy on whom I have mercy , and I will have compassion on whom I have compassion ."
(Romans 9:15)
But I personally have no problem with God sending everyone to hell who never knew Christ.
"For He says to Moses, "I will have mercy on whom I have mercy , and I will have compassion on whom I have compassion ." For the Scripture says to Pharaoh, "F or this very purpose I raised you up , to demonstrate M y power in you , and that M y name might be proclaimed throughout the whole earth ." So then He has mercy on whom He desires, and He hardens whom He desires. You will say to me then, "Why does He still find fault? For who resists His will?" On the contrary, who are you, O man, who answers back to God? The thing molded will not say to the molder, "Why did you make me like this," will it? Or does not the potter have a right over the clay, to make from the same lump one vessel for honorable use and another for common use? What if God, although willing to demonstrate His wrath and to make His power known, endured with much patience vessels of wrath prepared for destruction? And He did so to make known the riches of His glory upon vessels of mercy, which He prepared beforehand for glory, even us, whom He also called, not from among Jews only, but also from among Gentiles."
(Romans 9:15, 17-24)