What I meant is that it would be weird for an English speaker to have views on how Nahuatl words should be written using Nahuatl orthography, since different languages obviously have different orthographic conventions and associate different symbols with different sounds.

Oh, got ya - I thought they were talking about how English writes/pronounces its version of the word rather than how Nahuatl should do so! I agree fully in that case, it wouldn't make any sense at all for how foreign languages do something to dictate how another does - or to even expect them to be the same.