Hacha

[Ahuizote]

Thanks, I agree.....as well as in English you say An Hax, instead of A Hax....

The phonetics are playing a role, although it's correct to say "La Agua", "La Águila",etc.
At the end, a tradition changes the initial intention.
For example, for years and years,La Real Academia Española only accepted the name "Méjico", and it was very recently when they accepted the " X ".