Yeah, and the text does not actually say what you believe.
It just says in those (same) days were men of renown, heroes.
But God says nothing about them specifically there. Just that “My Spirit will not contend
with humans forever, for they are mortal; their days will be a hundred and twenty years.”
And also, The Lord saw how great the wickedness of the human race had become on the earth,
and that every inclination of the thoughts of the human heart was only evil all the time. The
Lord regretted that he had made human beings on the earth, and his heart was deeply troubled.
Nada about angels, or angel babies being the result of relations with women, or those supposed offspring being Nephilim.
That is all read in. Also: giants exist to this day. Are angels still having intercourse with humans???