The Holy Office later published an interpretation of its 1897 ruling on the letter of John:
At this response there arose on June 2, 1927, the following declaration, at first given privately by the same Sacred Congregation and afterwards repeated many times, which was made a part of public law in EB n. 121 by authority of the Holy Office itself:“This decree was passed to check the audacity of private teachers who attributed to themselves the right either of rejecting entirely the authenticity of the Johannine comma, or at least of calling it into question by their own final judgment. But it was not meant at all to prevent Catholic writers from investigating the subject more fully and, after weighing the arguments accurately on both sides, with that and temperance which the gravity of the subject requires, from inclining toward an opinion in opposition to its authenticity, provided they professed that they were ready to abide by the judgment of the Church, to which the duty was delegated by Jesus Christ not only of interpreting Holy Scripture but also of guarding it faithfully.”
It seems reasonable to take this more or less at face value. However, it is not really an interpretation of the meaning of the earlier ruling, but rather of its motive, and one that basically undercuts the original ruling.
Why was it necessary for this interpretation to be given privately “many times” before it was published? The original ruling essentially said that one could not even call the authenticity of the text into question. This would leave people who desired to be obedient to the ruling with no alternative but to firmly assert the authenticity of the text. Since many Catholic scholars could see that this went against the facts in manifest ways, there were consequently many who appealed in private for an interpretation which would permit them to question the authenticity of the text.
Even if we accept the basic honesty of the explanation, however, the original ruling exists in a broader context, of which the 1909 Pontifical Biblical Commission statement on Genesis is one example, which suggests a more general idea: the “audacity of private teachers” is doing damage to the Church, and therefore such audacity must be repressed. Regardless of whether repression was the correct response, the first part was true: damage was indeed being done. Audacity however was no necessary part of this process, since seeking the truth would do just as well.