I disagree.
I view this passage in the same way that I see Christians marrying non-Christians, for the same various reasons that people marry.
Sons of men were not followers of God. To me, the meaning seems clear. In a nutshell, God followers married nonbelievers.
It happens today and it’s that simple. Why is it necessarily so hard that it was that simple back then too?
Pretty women can get any man to turn his head, even dangerous women and many women will put up with bad men, provided that he is well off.