Slander doesn't just wipe off, even if you theoretically win a lawsuit. It's still "there", which is why it's such an insidious mortal sin. It violates the commandment, "Thou Shalt Not Murder".
So, how many innocent priests are you willing to sacrifice to drive out the homosexuals? I don't disagree with keeping them out of the priesthood, I do disagree strongly with this "expedient" method that will undoubtedly harm the innocent.
And yes, the Church has everything to lose: every good priest that fears they will be the next innocent victim of vicious slander will suffer, and every good candidate for the priesthood will rightfully rethink their decision if it becomes apparent the Church will not defend their own.
I do not see it the way that you do. If you do what is right, you have nothing to fear. Maybe I am missing something, but I have a difficult time believing that any priest that is not a practicing homosexual would be afraid of being falsely accused. Part of being a Christian is knowing that you have a chance of being falsely accused as Jesus warned. It comes with the territory. Those that are seeking to “expose” homosexual priests are doing this out of hatred for the Church. It is to their shame, and they will answer for it on the last day.