Mainstream anthropologists have much to say on the bullroarer, which has been a part of the diffusion debate for over a century:

“No ethnomusicologist, I think, would stand for plurigenesis as regards the bull-roarers, which even in decorative detail are often alike and are used for the same purpose wherever and whenever found.” ~Jaap Kunst, 1960

"The question is not whether the bull-roarer has been invented once or a dozen times, nor even whether this simple toy has once or frequently entered ceremonial associations. I have myself seen priests of the Hopi Flute fraternity whirl bullroarers on extremely solemn occasions, but the thought of a connection with Australian or African mysteries never obtruded itself because there was no suggestion that women must be excluded from the range of the instrument. There lies the crux of the matter. Why do Brazilians and Central Australians deem it death for a woman to see the bullroarer? Why this punctilious insistence on keeping her in the dark on this subject in West and East Africa and Oceania? I know of no psychological principle that would urge the Ekoi and the Bororo mind to bar women from knowledge about bull-roarers and until such a principle is brought to light I do not hesitate to accept diffusion from a common center as the more probable assumption. This would involve historical connection between the rituals of initiation into the male tribal societies of Australia, New Guinea, Melanesia, and Africa." Robert Lowie, 1920

"“The case for diffusion is even stronger than stated by Lowie. Not only is the bull-roarer tabooed to women when used in connection with male initiation rites, but it is also almost invariably represented as the voice of spirits. Nor does the bull-roarer travel alone in connection with male initiation rites. This paper has demonstrated the fact that a form of tribal marking, a death and resurrection ceremony, and an impersonation of ghosts or spirits is found among male tribal initiation rites as the usual concomitants of the bull-roarer. There is no psychological principle involved which would necessarily group these elements together, and they therefore must be regarded as having been fortuitously grouped in one locality of the world, and then disseminated as a complex.” Loeb 1922

Or, more recently:

“Interest has long since waned in ‘diffusionist’ anthropology, but recent evidence is very much in accord with its predictions. Today we know that the bullroarer is a very ancient object, specimens from France (13,000 B.C.) and the Ukraine (17,000 B.C.) dating back well into the Paleolithic period. Moreover, some archeologists—notably, Gordon Willey (1971)—now admit the bullroarer to the kit-bag of artifacts brought by the very earliest migrants to the Americas. Nevertheless, modern anthropology has all but ignored the broad historical implication of the wide distribution and ancient lineage of the bullroarer.” ~Thomas Gregor, 1973

And Bethe Hagen in 2009:

“The bullroarer and buzzer were once well-known and well-loved by anthropologists. They functioned within the profession as hallmark artifacts that symbolized the cultural relativist commitment to independent invention even as evidence (size, shape, meaning, uses, symbols, ritual) stretching tens of thousands of years across human history pointed to diffusion.” ~Bethe Hagen, 2009

Which ones of these are pseudo?