So then why do some Catholics give protestants flak for their own interpretation of the Bible?
This is an example of the Catholic Church making a conclusion…but at the end of the day, it is still men interpreting the Bible and drawing their own conclusions.
we give flak for personal interpretation, because it leads to relativism. You see it this way, I see it that way, and we can both be right.
However, it is still true that Catholic Biblical Scholars can and have made errors in interpretation. There is bound to be conflict when more than one person is doing something. Most of the time the scholars can just get together, review what they have come up with, and say, hey you got this right, but I think you could add this, or rephrase that.
And what comes about is one, generally accepted interpretation. However, nobody but the Pope is infallible, and he not even on everything. So could theoretically every Biblical Scholar be wrong about the Protoevangelium and how it relates to Mary, yes. is it likely, not really.
But if one holds on to “no, its my way or the highway” thats when heresy starts. It is generally when this happens that the Pope or Cardinals feel the need to “pick” which interpretation they agree with. However at this point it isnt just men, as Catholics, we hold that the Holy Spirit is active in such Councils and statements, so it isnt the men choosing, its God showing.