He said "Bible-believing Protestant. At a guess I would say around 1540 a lot of Protestants decided that the C of E was not "Bible-believing", and they've pretty much stuck with that opinion, while the C of E has done its best to live up to expectations. So I wouldn't consider Anglicans a refutation of FK's argument, be they never so Protestant.
A relative term. Which Protestant thinks he is NOT a "Bible-believing" person? If there is any unity among Protestants, it would be that each person believes that the Bible is the sole source of Christian doctrine. They freely interpret it as they see fit. Thus, even the most liberal of Protestants will fall back on "I am getting my interpretations from the Bible" and refute the more conservative Protestant who disagrees with them - even about homosexuality or women priests. (GACK!) And so disunity multiplies, as doctrines multiply as the number of heads increase in Protestantism...
Ask an Anglican if they believe the Bible. While Calvinists may disagree with their answer, it has no bearing, because we have now entered the realm of interpreting that book - and we fall back on why the Catholic Church is superior.
Regards