I was just talking about chemical drinks in general.
Anyway, here is some real chochma from the Starbucks kashrus site:
Soy Milk Non-Dairy
Use soy milk instead of milk in any beverage and it will be non-dairy, chalav yisroel.
Non dairy chalav yisroel?
Other than that, which shows sloppiness, the only real problem I found is that they recommend the use of this soy milk without mentioning whether it is supervised. Soy milk is a complex product. I also see no connection between the findings of that site, which match the CRC in many places, and the work of the “rabbi” you mention, who is indeed not reliable.