You are correct and the analogy of a Medical Doctor is a good one. The Medical Doctor still has the "powers" of medical treatment at his disposal even if his license to practice medicine is revoked.
If he performs medical procedures, those medical procedures are still valid, but he performs them illegally.
The same goes for a "defrocked" priest. Once a person is validly ordained a priest, he is a priest forever even if that man ends up in hell. His faculties as a priest, however, can be suspended or revoked. That is, his "license" to perform the duties of a priest can be revoked. This is called laicization -- returning the priest to the lay state (defrocked). The priest is still a priest, but he is no longer clergy. He is returned to the lay state. If a defrocked priest tries to say Mass, or offer confession, or perform any other duty of a priest, he does so validly as a priest, but does so illegally (without permission from the Church).
But in times of emergency, in danger of death, a non-clergy (defrocked) priest may still legally provide "last rites".
A defrocked priest also is no longer called "Father".
As for what happens with a priest discovered to be molesting children, the Church has handled that according to the advice given to them by the psychiatric community. Most of the situations for which we now hear so much about were situations in the 1960's and 1970's and some in the 1980's. At that time, the psychiatric community did not understand the dynamics of pedophilia as it does today. Thus the psychiatric community recommended the Church simply move the priest to a new parish to get him away from the one he was attracted to sexually. This, of course, does not work, but psychiatry did not understand that at the time.
Since the Church is not a psychiatric agency, the bishops trusted the psychiatrist on what to do with these priest.
This is not to say that there were not bishops who genuinely tried to cover-up things and not do as they ought, but the point is that most bishops were doing only what the psychiatric community told them. They made the BIG mistake of trusting psychiatry.
As to the charge of covering-up, in most cases the bishops were doing their job according to the moral imperatives of the faith. It is a bishop's job to try to avoid scandal. Scandal is one of the most dangerous things that can happen because it can adversely affect so many people. These sex scandal of the past few years is proof of that -- many Catholics have lost their faith because of the scandal. Yes, this is very immature of them, but it is the case nevertheless.
Scandal should be avoided at all possible costs, but this morally required need to avoid scandal is NOT suppose to be an excuse to not deal with the people who have done wrong. While it is a moral mandate to avoid scandal, it is also a moral obligation to hold the sinner responsible for his actions in a real and demonstrable way. It is also a moral obligation to provide pastoral care and concern for the victim.
The public blood-lust for fallen priests should not interfere with the moral obligations of the Church, or how the Church properly deals with these situations -- at least in a perfect world.
As a result, I am afraid that the Church has been pushed into the corner by the enemy and the blood-lust of the public to hand over fallen priests to the wolves.
This blood-lust is mostly against Catholic Priest even though fewer Catholic priest are involved in this sin than are Protestant ministers. In fact, among the molesters who are professionals the greatest amount of molesting is not with any sort of clergy at all, but with the mental health professionals.
According to study by the Wisconsin Psychological Society of the children who are molested by professionals, 66% are molested by psychiatrists, psychologists, and social workers, in that order. That same study found that clergy represented 11%.
Now I am not suggesting that this lets clergy off the hook, I am only pointing out the total perspective and the lack of blood-lust toward the largest group of molesters -- the mental health professionals who are suppose to help the children after they are molested by the clergy and other people.
Now keep in mind that the largest group of molesters overall are married men who are family or friends of the family of the child. But among professionals priest are the safest group one can entrust their children. I do not even think twice about leaving my grandchildren in the care of a priest, but I have great concern about leaving my grandchildren in the care of a social worker or other so-called "child welfare" worker or agency.
Anyway, back to your question. The Church has an obligation under God to offer pastoral care and concern, forgiveness, and assistance to a priest who has fallen. Burger King and Microsoft have no such obligation.
What does the Church do now?
I haven't kept up with the policies on this but one aspect of the Church policy is that criminal activity needs to be referred to the police authorities. To quote a statement from the Diocese of Denver's website:
"All incidents of sexual abuse of anyone under the age of 18 years of age, should be reported immediately to the civil authorities."
In addition a priest is usually either relieved of his duties or suspended pending the outcome of the investigation of the charges. If the priest is found guilty then he would be "defrocked" -- laicized -- removed from the clerical state. The Church will still provide pastoral care to the fallen priest as well as to the victims.
Bro. Ignatius Mary