"Priest" is a gender-neutral term, like "Doctor" or "Lawyer". You don't use the term "Doctress" or "Lawyerette". The single gender-neutral term applies to both male and female.
In typical usage, you would see "Priestess" only if it is an all-female clergy. That is obviously not the case here.
Baloney. The only reason why the words "priest" was used in the Church for the last twenty centuries is that only men could be ordained. And this will not change, because those who "ordain" women and such women themselves put are not in the Church anymore. They are in the anti-Church of Antichrist. Same applies to the openly "gay clergy".
In typical usage, you would see "Priestess" only if it is an all-female clergy. That is obviously not the case here.
The reason why they want the word "priestess" to be forgotten is OBVIOUS. Because this word has PAGAN connotations and as such is too revealing.