Your writing "down the line" is against the biblical narrative.
It fits the biblical narrative just fine. If you would just look previous to chapter 6 for additional context, you would see:
Gen 4:23 Lamech said to his wives: “Adah and Zillah, hear my voice; you wives of Lamech, listen to what I say:
I have killed a man for wounding me, a young man for striking me.
Gen 4:24
If Cain's revenge is sevenfold, then Lamech's is seventy-sevenfold.”
Notice the excessive violence of Lamech, in Cain's lineage.
Gen 4:25 And Adam knew his wife again, and she bore a son and called his name Seth, for she said, “God has appointed for me another offspring instead of Abel,
for Cain killed him.”
Gen 4:26
To Seth also a son was born, and he called his name Enosh.
At that time people began to call upon the name of the LORD. (ESV)
We see that at the time of the birth of Seth's son, "people began to call upon the name of the LORD."
Then, we should take note of this:
Gen 5:1 This is the book of the generations of Adam. When God created man, he made him in the likeness of God.
Gen 5:2 Male and female he created them, and he blessed them and named them Man when they were created.
Gen 5:3 When Adam had lived 130 years, he fathered a son in his own likeness, after his image, and named him Seth. (ESV)
Look at what isn't said--no mention of Cain or Abel. Right from Adam who was "made . . . in the likeness of God," to Adam's son Seth, who was "in his own likeness, after his image." It seems that both leaving out Cain and the similar wording of Seth to Adam and the creation of Adam are fairly significant.
Then:
Gen 5:21 When Enoch had lived 65 years, he fathered Methuselah.
Gen 5:22
Enoch walked with God after he fathered Methuselah 300 years and had other sons and daughters.
Gen 5:23 Thus all the days of Enoch were 365 years.
Gen 5:24
Enoch walked with God, and he was not, for God took him.
Gen 5:25 When Methuselah had lived 187 years, he fathered Lamech. (ESV)
Repetition is usually significant and something to pay attention to.
Gen 5:28 When Lamech had lived 182 years, he fathered a son
Gen 5:29 and called his name Noah, saying, “Out of the ground that the LORD has cursed, this one shall bring us relief from our work and from the painful toil of our hands.” (ESV)
Again, not insignificant that Lamech mentions "the LORD." And, we also see that Noah is the great-grandson of Enoch.
So, there seems to be a fairly consistent belief in God in all of Seth's line, but none in Cain's, which instead speaks of excessive violence.
No, you've defended it already.
Please stop with the false claims of racism and that others are trying to defend racism. It's unbiblical.
You're arguing Seth's righteousness and Cain's wickedness went on "down the line" to Noah's days, that's not in the text of Gen. 6
As I have shown, it's in the preceding chapters which clearly form the backdrop and necessary context to chapter 6. You're taking chapter 6 in isolation, which is not how to come to a proper understanding of anything in Scripture.
Notice where chapter 6 starts,
after giving lineages of Cain and Seth in the preceding two chapters, which I have provided:
Gen 6:1
When man began to multiply on the face of the land and daughters were born to them, (ESV)
Now we get into all humans multiplying, which would mean Cain's line and Seth's line. So, when we get to verse 2--"the sons of God saw that the daughters of man were attractive. And they took as their wives any they chose."--we have as the context, the lineages of Cain and Seth as well as them multiplying.
and it goes against the biblical narrative stated in Ez. 18:20 and Jn. 9:3.
Which have no relevance to what I am saying. I have already explained: "It has nothing to do with being a hereditary trait, so I don't know why you keep making that argument. Godly people have a better chance of raising godly people, and on down the line."
Do you disagree that godly people have a better chance of raising godly people, and on down the line?
Your argument "sons of God were Seth's godly line", which implies "daughters of men" were Cain's ungodly line, is totally invalid.
It is very valid, which is why at least some scholars also believe that is the case. It is possible that the sons of God were angels, but, given that they would have to have the creative power that only God has, it's more likely the stuff of fairy tales.