What I don't understand about this characterization is how it applies to Reformed Protestantism. Since when have the Reformed been known for promoting an individualistic interpretation of the Bible, the kind practiced by various fundamentalists with strong Anabaptist tendencies? Consider how the highly influential Louis Berkhof describes the formulation of dogma (emphasis mine):
The Church does not find her dogmas in the finished form on the pages of Holy Writ, but obtains them by reflecting on the truths revealed in the Word of God...it is not merely the individual Christian, but rather the Church of God as a whole, under the guidance of the Holy Spirit, that is the subject of this reflective activity. The spiritual man is the only one that is fit for this work, and even he can obtain a proper and adequate understanding of the truth in all its relations, and in all its fulness [sic] and grandeur, only in communion and in cooperation with all the saints...The formation of dogmas is not always a short process, nor is it a simple one. Its course is frequently determined more or less by long-drawn controversies. These are not always edifying, since they often generate a scorching heat and frequently lead to unholy antagonisms. At the same time they are of the greatest importance, and serve to focus the attention sharply on the question in debate, to clarify the issue at stake, to bring the different aspects of the problem into the open, and to point the way to the proper solution. The Church is largely indebted to the great doctrinal controversies of the past for its progress in the understanding of the truth.1
Note that these profitable controversies could never, of course, occur in the mind of one individual sitting alone in a closet with his Bible. And Berkhof continues after this point to discuss the role of the Church in formally accepting the formulation of dogma, again rejecting the idea of supremely individualistic interpretations of Scripture holding any sort of higher or final interpretive weight.
Roman Catholic lay-apologists should appropriately characterize the Reformed approach to Biblical interpretation by treating it as fundamentally distinct from other groups with certain Anabaptist tendencies. Perhaps then their appeals to unity arguments can be reworked and taken as credible objections to the Reformation and its principles.
1. Louis Berkhof, Systematic Theology, New Combined Edition (Cambridge, UK: Eerdmans, 1996), 23.