This is a bad idea for several reasons, not the least of which is that the Esperanto version of the Latin alphabet itself uses a number of unusual diacritics which are important for disambiguating words.
I would assume that "Esperanto written in pure ASCII" is referring to x-sistemo, which avoids the diacritics
I would assume that "Esperanto written in pure ASCII" is referring to x-sistemo, which avoids the diacritics