You and the people you quote from all assume that Protestantism is united like Catholicism. Protestants separate over error necessarily and become completely separate groups. Catholics, on the other hand, ignore what's going on in the local churches. Also, the Catholic church has changed over the centuries with the culture. That's why I can go into several Catholic churches in different towns and find contradictory doctrines, many of which are against Scripture and heretical to established Catholic doctrine. Protestants aren't united, and don't claim to be. Catholics aren't as united as they claim to be.