Are you claiming that the sola scriptura-like approach is actually an element of Theravada Buddhism or that the positions being defended with that approach are actually the distinct tenants of Theravada Buddhism? (I mean, I get from the repeated references to the Pali Canon that the arguments—framed as general to Buddhism—are likely Theravada-focused, but that doesn't really answer the question I was asking.)
Yes, it goes as far as some Theravada traditions not giving much attention to Theravada's own commentary corpus, which was added centuries after the Buddha's life.
The "let's go back to origins" approach is not a Western invention, the existence of Chan/Zen proves it quite clearly.