The answer seems quite simple (not to mention logical). Why would the Church want teachers, within their own institutions, leading hearts and minds away from the fullness of truth found in the Catholic Church? The world gives every mind the opportunity to learn secular "truths." Why invite the secular mindset into the Catholic classroom for any reason other than for purposes of debate and response? The Church doesn't need teachers like Sister Akers encouraging young women to acts of disobedience that would ultimately lead to excommunication.
I wondered though, how firm the Church's stand on this issue really is. I've read work by male priests who stand with the feminists and loudly proclaim that this is open to debate and not dogmatic teaching. Yet John Paul II's letter is incredibly clear:
"4. Although the teaching that priestly ordination is to be reserved to men alone has been preserved by the constant and universal Tradition of the Church and firmly taught by the Magisterium in its more recent documents, at the present time in some places it is nonetheless considered still open to debate, or the Church's judgment that women are not to be admitted to ordination is considered to have a merely disciplinary force.That doesn't sound like it leaves any room for argument and he didn't intend it to. This belief is to be held by the Church's faithful and at the very least one would expect that this teaching would be held true in the Church's institutions (although Catholic Colleges seem determined to disappoint again and again).
Wherefore, in order that all doubt may be removed regarding a matter of great importance, a matter which pertains to the Church's divine constitution itself, in virtue of my ministry of confirming the brethren (cf. Lk 22:32) I declare that the Church has no authority whatsoever to confer priestly ordination on women and that this judgment is to be definitively held by all the Church's faithful."
While Ordinatio Sacerdotalis is a relatively short letter (and I strongly recommend reading it for yourself) it has far more wisdom than could fit into one blog. There will be more to come!