There is a kind of strange logic behind the decision. Homosexuality, per se, is not immoral in the eyes of the Church. The Church does not teach that the state of being gay is inherently sinful, at least not anymore. But acting on it is. Gays are required to live a life of abstinence from sexual pleasure, I guess in the same way that unmarried heterosexuals are. With all the great success that follows from keeping high school kid's paws off each other.
Carla Hale's biggest sin was in making her status public, even if that was not her intent. By having her married status printed in the paper, she forced the hand of the principal and of the bishop. Given the current state of affairs in the Church, I can't imagine this turning out any other way. The bishop cannot condone a public "sinner" to continue without some sort of punitive action. And Hale was not likely to dump her spouse to keep her job.
The message to gays is that the Church is OK with your status, as long as we can all pretend not to know about it. But as soon as our veneer of deniability is removed, we will act decisively against you. The sad thing is that all of this "action" on the part of the school runs up against the Church's supposed stand for justice and truth. We are now a Church where truth has become a weapon. Make the truth of your gay marriage public, and you're fired. Publicly support the truth of your position about abortion rights, and you'll be denied communion. Publicize the truth of the Church's cover-up of pedophile priests, and you'll be accused of scandalizing the faithful. The truth is not important. What is important is to preserve the ability of the faithful, priests and bishops to keep themselves aloof from sin, even as it swirls all around them.
It's a "see know evil" approach that makes liars out of all of us. Longtime Church members know the game and have learned to play along with the priestly game of secrecy. Don't tell us about your contraceptives,and don't challenge us when we preach against them, and we will baptize and marry your kids and bury you when you die. Don't write articles and stories about your divorce or your abortion, and we will let you take communion and run the bake sale. Keep mum when the confirmation teacher tells your kids that evolution is a myth, and we'll let your teen get the sacrament.
The Church needs to undergo an enormous change of heart, and allow so-called sinners to become part of the conversation. The culture of secrecy has to go, and with it, the hypocrisy that snares good people like Carla Hale in a web of secrecy and dishonesty.