Exactly We used to have an old pastor who believed in this stuff and every time he would mention it he would say that angels "cohabited" with women. But the King James Bible clearly says that the individuals in question took "wives".
What does 'wife' mean though? In a time/place of depravity?
Mohammed's 'wife' Safiyah -
According to the Hadith, Safiyah did not have a choice in this marriage; she was war booty for Mohammad,
not an uncommon practice at the time. She and her husband were captured after Mohammad's conquest of Khaybar.
He tortured & murdered her husband Kinana and murdered her father after taking them as prisoners of war.
The Hadith narrations agree that Mohammad chose her due to her exceeding beauty, as had been his custom where
the Muslims took slave women as booty, such as the conquest of the Banu Qurayzah.
Similarly the Genesis 6 account could have been part of an act of war against mankind.
That isn't to say that the women (or some of them) didn't cooperate willingly. Just that we can't assume they did
based on our understanding of how marriage should be.