More accurately I am saying that when a privately arrived at understanding is at odds with the meaning that the Church has held for 2000 years, then the person with that inorthodox opinion has the onus to explain why the Fathers of the Church missed his meaning. Mos tlikely, the error is on the private interpreter, who reads the bible in a translation, often a very bad one, in the context of a very different culture. As we have seen, even very plain words, such as "brothers" did not have the same meaning then.
Of course we don't have to run to the Catechisis or to St. Chrysostom, or to the writings of the Popes, or to the councilar documents each time you read the scripture. Nobody does. About 80% of the Scripture is very clear to a casual reader. But not 100%. In order to read the scripture and profit from it spiritually one has to absorb the Holy Tradition at the same time. Then he can read for wisdom and pleasure and grow in faith with it.