Divisions have existed in Christianity from the start. But the division has always been clear (Orthodox vs. Heretic, Shismatics). When Protestants talk about Catholicism, what are they referring to? The Old Catholics? The Sede Vacantis Catholics? The Feeneyites? No. They are referring to those churches in communion with Rome. They recognize that the Pope speaks for Catholicism and represents true Catholicism. Moreover, the Catholic splinter groups are just a handful compared to the diversity in Protestantism. A diversity that has existed from its very beginning. You may not see a problem with that, and that’s okay. But Christ founded ONE church with ONE set of doctrines.
The Bible describes the church as being the pillar and foundation of truth, not the pillar and foundation of truths mixed with false doctrine or errors. The fact that there is so much diversity in Protestantism demonstrates that there are errors and false doctrines, because God’s truth cannot contradict itself. If the Lutherans are right on baptismal regeneration, then all those who oppose it are teaching false doctrine. They may be sincere and love Christ, but it is false. And false doctrine does not come from God. If Christ is trully present in the Eucharist, then all those who teach otherwise are teaching falsehood. Why is it that sincere Christians looking for the truth in the Bible but come up with compeletly different conclusions? Why is it, Sola Scriptura, that you see infant baptism as a necessary conclusion drawn from the Bible while other Protestantism see it as pure conjecture and as Biblical as the Immaculate Conception? Why is it that Lutherans see baptismal regeneration as clearly taught in the Bible, but you see otherwise? If all Christians possess the Holy Spirit, why do they disagree?
Doctrinal error is a result of human sinfulness. God’s truth is one and the church is the pillar and foundation of truth, not the pillar and foundation of truth mixed with error. In order to fulfill this vocation and the promise that the gatesof hell will not prevail against it, The Bible needs an objective interpreter that can withstand every wind of doctrine and error. Sola Scriptura has proven this. The Bible alone has been used to promote a number errors, such as Oneness Pentecostalism. All of the Catholic splinter groups you pointed out have appeared in the last 150 years. Considering that the Catholic Church is nearly 2, 000 years old, that’s not bad. Protestantism, on the other hand, has been fractured from the start and for the last five centuries has continued to splinter. Since the nineteenth century, for example, we’ve had the rise of the Adventists, Pentecostals, Holiness, etc. There is no indication that this splintering will end.
There are debates within the Catholic Church. But you don’t have the Thomist Catholic Church, the Molinist Catholic Church, the Sungenian Catholic Church, the Keatingian Catholic Church, etc. Like I said, there will always be dissent as long as there sin. But this dissent is not a legitimate alternative to the truth and the level of dissent in Protestantism far surpasses that in Catholicism.
God Bless,
michael