There is a controversy about whether white people can sing the blues. Some say that all white blues are inauthentic. Others reply that no one could tell Jo Ann Kelly was white by listening to her sing. The first group would say her blues were inauthentic anyway. It doesn’t matter how they sound; if you are white, it’s not real blues. It’s just a rip-off. It’s a fake imitation.
According to its visionary history, the Aro gTer originated with Kuntuzangmo, who gave it to Seng-ge Dong-ma, who gave it to Yeshé Tsogyel, who gave it to Aro Lingma, who gave it to Ngak’chang Rinpoche. As a matter of objective truth, it is likely that only the last of those people existed.
This is the usual pattern for termas. They originate with gods, pass through the hands of mythical people, and are finally delivered in visions to the living lama who writes them down.
So there is nothing odd there. What is unusual is that Ngak’chang Rinpoche is a white guy. So, the Aro gTer appears to me to be an authentic Nyingma terma, but maybe not a Tibetan terma.
Most termas have been delivered to Tibetans, but not all. There are Bhutanese termas. The Bhutanese are quick to tell you they are not Tibetans. There is at least one Mongolian terma system. Mongolians are completely different from Tibetans ethnically, linguistically, and culturally. But to Western eyes, they look pretty similar.
white people are too ordinary
I suspect that many students believe white people can’t have authentic religious visions, and can’t receive terma. White people are just too . . . ordinary for that. Maybe I am wrong; I have never heard anyone say this explicitly. Certainly, there seems to be nothing in Tibetan Buddhist doctrine that supports that kind of racism.
Western students of Tibetan Buddhism often seem to me to accept anything that comes from Tibet as “authentic.” This is convenient, but it is not the Tibetan view. In fact, the majority Tibetan view is that anything that originates in Tibet is inauthentic! For most Tibetans, only scriptures from India are valid. And there is violent disagreement among Tibetans about which texts are authentic. Uncritically accepting everything from Tibet makes no sense in Tibetan terms.
If the Aro gTer were taught by a Tibetan guy, would anyone in the West question it?