The Truth of the matter is in Genesis chapter 6 , 2 Peter 2:4-5 , Jude 1:5-7
This is the verified account as to 'WHY' God destroyed all 'flesh' that was not in the Ark.
Fallen Angels cannot be Saved = there is no Redemption for them.
When the angels came to earth they crossed the point of no return and became part of "this age" and as such were able to procreate
"sons(male) of God with the daughters of men".
"And the angels who did not keep their proper domain(spiritual realm), but left their own abode(spiritual realm), He has reserved in everlasting chains under darkness for the judgment of the great day; as Sodom and Gomorrah, and the cities around them in a similar manner to these, having given themselves over to sexual immorality and gone after strange flesh, are set forth as an example, suffering the vengeance of eternal fire.
The offspring of this mixture cannot be Redeemed, thus the wickedness that was produced by the corrupt teaching, methods and perversion of these fallen angels mixing with mankind could not be left unrestrained by God.
When the angels became part of "this age"(Luke ch20) their offspring became part of "mankind" by mixing with "daughters of men".
A superior race of mankind that could not be Redeemed = "Men of Renown" and "Giants"
This is why only Noah and his family made it into the Ark.
Which brings us right to back to Noah's day and Revelation = "unless the LORD had shortened the days- no flesh would be saved."
Anyone who rejects the verification of 2 Peter ch2 and Jude are left with 'their own' explanation that cannot be found in scripture.
