again...I reject the idea that angels had sex with easy earth girls.
I believe its the wrong way to read the whole story.
I believe that when you go slow and read the whole Genesis story in context you don't find anything all that different in this part of the story at all.
In Genesis 4 you read about one side of the family tree of human
In Genesis 5 you read about the other side of the family tree of humans
and then in Genesis 6 you read about what happened when one side mixed with the other....
It's that simple of a story to read and understand.