I don't see how that shows that "free love" is supported by credible scientific research.

Worth noting is that Mead herself had an adulterous past. Sexual misbehavior can produce feelings of guilt and disgust with oneself, and one (unhealthy) way to try to cope with that guilt is to rationalize one's misbehavior. If Samoans, seen through modern Western eyes as a representation of the "pure state of nature", can be shown to be promiscuous, then, according to this highly tendentious and fallacious interpretation, promiscuity must be "natural", the state of nature, and it is the West, or perhaps even "civilization" in general, with its weird sexual hangups, that is in error. So why feel guilty?

Of course, as the aforementioned expose shows, there were Samoan police records of men with broken jaws or whatever that contrary to Mead's account, Samoan men expressed exactly the kind of reaction to their wives' adulterous affairs as one would expect. Not that contrary evidence would change anything anyway.

Aldous Huxley admitted to a similar rationalizing process, but one that was even more deeply offensive from a metaphysical point of view. He admitted that the real reason he and those of his generation and his milieu celebrated a nihilistic view of life is to rationalize their own promiscuity. If nothing means anything, then why not sleep around? Of course, he later had the honesty to admit his motives.

Alfred Kinsey is another one we can add to the list. Kinsey himself suffered from sexual pathologies, and his "studies" were riddled with selection bias wherein the selection of those he interviewed skewed heavily toward sex criminals and people with various sexual disorders. Never mind the sexual abuse of children he engaged in.

We could add Reich, Freud, Satre,... to the list.

Are you slut shaming Margaret Mead?

I don’t think people are so simple - that Aldous Huxley joked about wanting more sex doesn’t convince me that’s truly the driving force of his entire life. And, just practically speaking, a smart scientist man could live a sex-filled emotionless life at that time, and still today… you don’t need to be a nihilist to go on Ashley Madison or seek a Sugar Baby.

More substantively, it seems like you’re endorsing a view that Wikipedia sums up as anti scientific and biased. I hate to dismiss someone so blithely but it is fairly strongly worded. To quote the spiciest parts:

  Freeman's book was controversial in its turn and was met with considerable backlash and harsh criticism from the anthropology community, but it was received enthusiastically by communities of scientists who believed that sexual mores were more or less universal across cultures. Later in 1983, a special session of Mead's supporters in the American Anthropological Association (to which Freeman was not invited) declared it to be "poorly written, unscientific, irresponsible and misleading." Some anthropologists who studied Samoan culture argued in favor of Freeman's findings and contradicted those of Mead, but others argued that Freeman's work did not invalidate Mead's work because Samoan culture had been changed by the integration of Christianity in the decades between Mead's and Freeman's fieldwork periods.

  Eleanor Leacock traveled to Samoa in 1985 and undertook research among the youth living in urban areas. The research results indicate that the assertions of Derek Freeman were seriously flawed. 

At the least, I think we should all agree that no one was out to “prove the way humanity should be”, just explore non-western ways of life. And I believe the consensus among gender theorists and anthropologists is that western sexuality is arbitrary in many ways. That’s not a condemnation of every single part of it, especially dishonest adultery as you seem focused on, but it’s certainly a reason to investigate non-western society’s IMO.

But you can't really dismiss criticism of her work as being from just a bitter rival. Whatever his personal motivation for doing it, Freeman and later anthropologists talked to Samoans themselves (some of whom were alive when Mead was doing her study of their society) and they didn't agree with Mead's description of them.

It seems Mead and Freeman experienced a slice of life from different parts of Samoa, which was summed up for me in this part of the wikipedia article:

"Samoan culture had been changed by the integration of Christianity in the decades between Mead's and Freeman's fieldwork periods" ... "Leacock pointed out that Mead's famous Samoan fieldwork was undertaken on an outer island that had not been colonialized. While Freeman had undertaken fieldwork in an urban slum plagued by drug abuse, structural unemployment, and gang violence." [1]

Note that doesn't necessarily mean that Freeman's island perfectly resembled Mead's island prior to its urbanization – I'd wager, rather, that Samoan society was diverse!

1 - https://en.wikipedia.org/wiki/Margaret_Mead#Criticism_by_Der...