I've heard that Briffault's law bullshit many times, and I've read it and it really doesn't make any sense. The TRP and MGTOW community justifies Briffault's law with the woman choosing the beta provider and then the beta provider finishing the child rearing and going with the dominant alpha or the beta taking care of the child that is not his and that child was the product of a dominant alpha and other nonsense. My doubts and some statements are:

The community links a law applied to animals and it is: why does the "alpha" male have access to 80% of women and applies the law to the alpha male?

They take a law out of context just to explain the promiscuity of women, that their children are not theirs and the infidelities. When the law has nothing to do with the law. And why the hell would the TRP/MGTOW community in the middle of 2021 take a 1919 law seriously?

When it is clearly impossible to know human behavior due to the complexity of us, cultural influence, emotions, upbringing, instilled values, environment, there are so many things that the human being becomes something very complex to explain their behaviors and linking only to biological behavior is absurd because we are not primitive.

Briffault's law has a lot of loopholes and nonsense to which the community uses the law to affirm their requests.