Your making it COMPLICATED.
Breaking it down real easy
The words of not only this prophecy, but many prophecies ARE going to be sealed to most and they will never get true understanding because they are either
A. Taught and lead to believe only what they are taught and shown can be true, that if their teachers don't have it right they can't because its not time or that they don't even understand the wrong understanding of their teachers and assume there is something wrong with them
OR
B. They become like what the WT likes to quote as the Ethiopian Castrate who had no said how can I understand these words if nobody to teach me? (They say that ONE scripture which goes contrary to hundreds showing how you can get instruction by God directly, but that one scripture overrides all that you CAN"T learn the bible and prophesy on your own, when it really was showing that he just had no faith he could understand without being shown and fed 'milk'. If you don't believe or have faith, don't even think you'll get anything. )
It's only those who seek the treasures, who put faith and try to get understanding, at the very least 'verify' everything they believe and not shy away if the holy spirit is trying to correct and show them the correct understanding.