The Catechism makes an entirely rational declaration about biblical hermeneutics.
[A]ll that has been said about the manner of interpreting Scripture is ultimately subject to the judgement of the Church which exercises the divinely conferred commission and ministry of watching over and interpreting the Word of God. [§119, quoting Dei Verbum §12.3]
If the Church doesn’t have the final say when it comes to Scripture, then who does? And why should we accept that authority over the Church’s? If we suppose that scholars should have the final say, there are some obvious questions that don’t have any reasonable answers. Why should we accept their authority when it comes to knowing the meaning of God’s Word? Since scholars disagree about practically everything related to the Bible, which one(s) should be our authority? How do we identify them? Any resolution of these problems is ultimately going to be ad hoc.
If we say (what seems very reasonable at first) that God should have the final say, there are likewise impossible difficulties: How do we know what God’s final say actually is? We can’t simply appeal to the Bible to learn what His final say is. For starters, that’s a circular argument. Secondly, we’re left asking: who says what God’s final say is? Subjectivism is the inevitable consequence here, just as it is if we say that the Holy Spirit tells Christians directly (without the mediation of the Church or anyone else). Christians disagree about seemingly everything in the Bible. If the Holy Spirit really does directly tell Christians the meaning of the Bible, then He must contradict Himself an awful lot. And that, of course, is impossible.
There is no other reasonable alternative than for the Church to have the final say with regard to the interpretation of Scripture. The alternatives land us in subjectivism.