Many Christian philosophers and theologians would agree that there is some sense in which these two propositions are true:
1. Our understanding of the revealed truth is limited.
2. There are multiple legitimate interpretations of many passages of Sacred Scripture.
For some people the senses in which these propositions are true entail:
3. No one Christian tradition is superior to the others with respect to the soundness of its teaching.
But, of course, there is a plausible way of understanding 1 and 2 such that they do not entail 3. Consider that it is reasonable to admit that my knowledge of X is limited without also having to concede that my knowledge of X is no better than that of others who also have some familiarity with X. I may know that God has an intellect and will and you may know this too but suppose that you understand how these relate to the act of creation and I don’t. And suppose further that neither of us really understands how the three Persons of the Trinity have the same intellect and will. With respect to these topics it is true both (a) that you and I have a limited understanding of revealed truth and (b) that your knowledge is superior to mine.
In regard to interpreting Scripture, let’s say that A sees Jesus’ resurrection as a sign of Jesus’ victory over death, B sees it as a promise of the possibility of resurrection for all who believe in Jesus, and that A rejects B’s reading and B rejects A’s. Suppose a third person, C, understands (rightly, as most people would recognize) that both interpretations are legitimate and not in conflict. Clearly, on this point C’s view is superior to both A’s and B’s.
Thinking of these examples as having analogues with Christian traditions, it is evident that you could hold 1 and 2 above to be true and not believe that they entail 3. Indeed, it is quite conceivable that some Christian traditions are superior to others.
Merold Westphal is someone who, as far as I can tell, thinks that 1 and 2 are true in a sense such that they entail 3. One place where you can find Westphal making the case for this is in his book Whose Community? Which Interpretation? Philosophical Hermeneutics for the Church. I understand 1 and 2 differently from Westphal. And I happen to think that some Christian traditions are superior to others. If you have the time and the inclination, you might have a look at my review of Westphal’s book.