Then you must have closed your eyes when Catholics contrive to support their traditions, in which the parameters of Rome, which rarely has infallible interpreted verses (how many being a matter of interpretation), yet allows such things as one RC contending that Ps. 93:1 teaches geocentrism and another heliocentrism, or that no one else but Jesus and Mary are said to be “highly favored,” “full of grace,” (Lk. 1:28) while another sees that in Acts 6:8; (cf. Eph. 1:6), or that 1Cor. 3 is speaking about purgatory, and another only uses it to affirm that fire consumes, or for one to contend that Rv. 12 cannot be speaking about Israel and another believe it is (at least primarily) etc.
And the lack of comprehensiveness or perspicuity of the magisterium not only allows disagreement about Scripture, but about what certain teachings of the magisterium mean, such as whether Lumen Gentium means sincere former RCs like myself can be saved outside formal submission to Catholicism, as well as multitudes more things that are not clear or not officially addressed.
And you yourself provided an example of this, as the “great liberty to interpret Scripture” (even with a magisterium) comes from a far more noted apologist than yourself:
“The liberty of the Scripture interpreter remains extensive. Taking due consideration of the factors that influence proper exegesis, the Catholic Bible interpreter has the liberty to adopt any interpretation of a passage that is not excluded with certainty by other passages of Scripture, by the judgment of the magisterium, by the Church Fathers, or by the analogy of faith. That is a great deal of liberty, as only a few interpretations will be excluded with certainty by any of the four factors circumscribing the interpreter’s liberty” Jimmy Akin,, Catholic Answers (http://archive.catholic.com/thisrock/2001/0101bt.asp)
Meanwhile, rather than a free for all, evangelical-type denominations and churches for whom Scripture is paramount typically have their own magisterium (as does Rome) and overall affirm the Apostle’s Creed and or Scripturally substantiated conflating statements defining who God is and what Christ did and related basic truths, especially the primacy of Scripture and salvation by grace to save the damned and destitute sinners, (vs. some hope in earned credits and or the power of the church), under the premise that Scripture is infallible, and which magisterium typically requires assent of these truths by members.
And which common consent is manifest, among other ways, in a shared contention against those who deny these common essentials (“cults”), as well as against certain traditions of Rome.
These evans also manifest a great degree of transdenominational fellowship, but do differ in many things and have formal divisions, but so does Catholicism, the differences being a matter of degrees, while under sola ecclesia is seen the greatest aberrations, as this is what cults effectively operate under (the “Living prophet” and the WTS being as infallible popes).
Like you have stated many times, the Catholic Church allows quite a bit of freedom to its members to "interpret" for themselves those things not specifically spelled out in their Catechism and even WITH that catechism, some veer from it how they please and even those set up to be the leaders do so, as well, with impunity. It would be nice to hear some honesty once and awhile about this fact. Like your charts and surveys show, those who claim to be joined to the "one, true church" lack a lot of unity on even the major things, much less the minor ones.