The truth is that there is controversy over when celibacy became a common practice; Gregory VII apparently still had a problem on his hands in the eleventh century because he had to go further than anyone had gone before in nullifying the marriages of ordained priests. This, seven hundred years after celibacy was first "Official" Church policy.
Seems the issue is less and less on the table as time goes on. Yesterday JPII's comments to the Nigerians; today's Zenit article posted by me.
Nobody ever seriously thought that John Paul II would discuss optional celibacy. But, he clearly won't silence those who wish to discuss it.
Are you kidding? What do you think he meant to do with his comments to the Nigerian Bishops?
He would like them to shut up and stop whining but he is far too polite to put it quite that directly.
As to Middle Ages married priests: has it occurred to you that various sins have been practiced, often by large populations, for long durations, despite the existence of the 10 Commandments since about, say, 5000 BC?
The fact that people ignore Commandments and/or disciplines does NOT mean that the Commandment or discipline did not exist.
Perhaps at another seminary you would have learned logic 101, as well as analogy.