That’s one of the theories out there. Might be true, might not be.
Either way, it didn’t take but about 4 generations later for the Nephilim to be back into the picture again.
I suppose that it doesn’t make much difference, except to show that the demonic is still actively trying to pollute the human race.
Would that be because those genetically corrupted humans are not candidates for salvation?
Since the Messiah has come, corrupting the human genome would not have the effect of preventing His coming, so there has to be another reason for it.