Back in the day, there was only one Vampire, and he made a limited number of other Vampires who in turn made all the Vampires right up until the present day. Some posers decided that they wanted to be Vampires, too, and they had their canine teeth altered and starting acting like Vampires. The head Vampire scoffed at them and reminded everyone that the posers weren’t real Vampires at all.
Substitute Apostle for Vampire and Pope Benedict for the head Vampire and you get the idea of where Benedict was coming from when he announced that Protestant churches aren’t “real” churches. Saint Peter had some special mojo that he transferred to a select few who, by laying on hands, spread the mojo to the bishops. You can’t get the mojo from any other source. That’s why rebellious Catholic congregations are keen to get excommunicated bishops to make priests for them. Without that episcopal mojo, the priests can’t work their juju, and everyone will go to hell.
Of course, Pope Benedict could take no other position. The whole edifice of the Catholic Church is based on the concept of the apostolic succession. Without it, the institution could not plausibly claim a monopoly on contact with God and on salvation. Roman Catholicism would be pointless without it. The CEO of the Catholic Church has to stand up for the prerogatives of the institution.
I don’t really care what Benedict thinks about my church. Here’s what I think about Benedict: He’s a weird guy who likes to wear funny hats, but he is also a man of faith and principle whom I mostly respect. He is entitled to his opinion on spiritual matters, just as I am entitled to mine. My opinion is as good as the Pope’s as far as I am concerned.