Great Sage,
You do make some valid points: Hmong people do not know their true origin (homeland), the original language may likely be neither White or Green, and language evolves over time and due to environmental factors or influences.
As a whole, those points are indisputable. But on a purely scholastic and/or scientific level, I believe we, Hmong, need to start looking for answers. These three among others need answers or at least sound scholarly explanation. (I won't go into as to why?)
Seriously, how can one claim to be a people, and not know or try to find the simplest answers to their existence and being? Namely, what is our origin (ancient homeland)? What is our native tongue, culture, and custom etc.? And how have we evolved and have been evolving? If you look at all the developed (educated and intellectual) countries and nationalities throughout the world, throughout history as a matter of fact, they know with some great certainty the answers to these three simple question. That for the most part, is my biggest proponent and argument about having these types of discussion or debate - questions to be answered. (Beyond that, yes, people will have their bias and personal opinions - founded or unfounded in scholarships and scientific research. That is fine too.)
And I am not trying to accuse the Green Hmong, but, the initial conjecture that the Green dialect, culture, custom, and people were in fact the original Hmong of our ancestors were in fact made by them or their elders. There is even a U-tube video specific to this posture. Look for it if you are curios, if it is still available, that is.
Lastly, in nature, what generally happens to the original species as it evolves or migrates. Simply put, it becomes "extinct". And we all know that as a whole, there are 10-times plus more Green Hmong than White Hmong globally, even in the West (US, Canada, etc.). I have already said this, but N. Tapp concluded in one of his research publication, that the White Hmong are "extinct" in SE Asia and China. The few remnants have all but immigrated to the West.