Well, you were using it to beat up GP_Humans on using his “private interpretation” of scripture.
That is not what the verse means.
How were the prophets of old able to predict with such astonishing clarity and accuracy the things about Jesus? Peter tells us plainly in verse 21: “no prophecy was ever made by an act of human will, but men moved by the Holy Spirit spoke from God.” The Spirit of God revealed these things to them. They were not making guesses about the Messiah. In fact, they were not even making educated guesses. What they predicted was not a matter of them arriving at some interpretation of events they saw in their own day. This is what Peter means when he says “no prophecy of Scripture is a matter of one’s own interpretation.”
2 Peter 1:20, then, is about the prophets and how they made their predictions. It is not about the more general issue of interpreting the Bible. 2 Peter 1:10 is not about whether anyone must or can interpret the Bible.
St. Peter is clear that Scripture is not for private interpretation which you and your comrades conveniently choose to ignore at your own peril.
"And account the longsuffering of our Lord, salvation; as also our most dear brother Paul, according to the wisdom given him, hath written to you: As also in all his epistles, speaking in them of these things; in which are certain things hard to be understood, which the unlearned and unstable wrest, as they do also the other scriptures, to their own destruction." 2 Peter 3:15-16