As far as these beliefs not being a part of the Catholic Church, you're absolutely right.
Outside of the issue of inclusion in Church teachings however, taken on their own merits, "deaconesses," Mary Magdalen and the Gnostics are hardly considered "garbage" by many millions of people. Disagree with their beliefs if you'd like, but unless you accept a discussion wherein Catholicism may be referred to as "garbage" by those not of the faith, your language should be kept more civil.
No, it’s garbage.
The problem here is that the whole riff on "deaconesses", Mary Magdalen, and the Gnostics was created specifically to attack the Catholic Church. It has no basis in historical fact.
A bunch of people believe it solely because they were deluded by Dan Brown and his ilk in the popular press. If scores of people run around in a panic because they believe that Martians are landing in Grover's Mill, that doesn't make it true just because a lot of people believe it. It just makes them victims of a hoax.
Moreover, Brown may well just be in it to make money, but plenty of liberals within the Church push that garbage because they want to recreate the Church in their New Age image.
If you don't like the word 'garbage', we can say, 'deliberately manufactured falsehood to discredit Catholic beliefs'.
They're coming for all Christians next, you know.
No, it’s garbage. Deaconesses is a mis-translation; it didn’t refer to an office, but to what we would virtually call “volunteers” nowadays. These were women who volunteered to help (serve, diakonia) with women converts, since men could not help them with their baptism, etc., since it usually meant disrobing and required personal contact. But it was not an ecclesiastical office.
As for Gnosticism, nobody ever treated women worse than the Gnostics. Women were unclean; Gnosticism is one of the precursors of Islam. Do a little research. There’s no reason to be civil about Gnosticism or the heresies inspired by it.
Quid est veritas, garbageman?