The Zaid and Zaynab tale: misdirection for theological purposes?

What is the point in the tale of Muhammad supposedly marrying his adopted son's wife, Zaynab?
Source: Ted Talk https://www.youtube.com/watch?v=GZGY0wPAnus

Sneaker's Corner seeks to comment on and share some of the key moments from Speaker's Corner. Another goal is to explore in a critical way the origins of Islam, and in this regard, I must credit the work of Dan Gibson, Patricia Crone, Angelika Neuwirth, Jay Smith, Hatun Tash, David Wood, Robert Spencer, Douglas Murray, and many more who from different backgrounds have been asking challenging questions and contributed to my current understanding of Islam.
Stock footage is from videvo.net.

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