Well, first of all, Gelugpas are not rang stong pas, even Khedrupje rejects this appellation for their view and heaps ridicule on it.Sherlock wrote:Why is rang stong said to err towards nihilism? I don't get this common remark by gzhan stong pas. Rang stong is actually a realist position, they only limit their emptiness to svabhavas, very similar to Sautrantikas, so it is very confusing to see them claim to be Prasangika.
Also I always found this terminology of translating inherent existence or some other variant very confusing until I learned that it was just svabhava/rang bzhin. Using the Sanskrit really makes everything clearer.
Second of all, the reason why Gelug view leans towards nihilism is the insistence that ultimate is merely "the emptiness that is the absence of true existence in things". Hence they assert the ultimate is a mere nonexistence, and that leans towards ucchedavada.