Indeed it's striking, and, as the story goes, he wrote it down immediately after his vision ... so it probably reflects the content of what he saw. Now, some claim that the vision never happened, but it appears that at least one or two credible sources reported it.
In any case, what I wanted to call out is that the text is in the PAST TENSE, as if it has already happend. Except that it hadn't yet. So that speaks more and more to how he saw something in his vision that had happened in the future, namely, the replacement of the See of Rome with some throne of abominable impiety.
These most crafty enemies have filled and inebriated with gall and bitterness the Church, the spouse of the immaculate Lamb, and have laid impious hands on her most sacred possessions. In the Holy Place itself, where the See of Holy Peter and the Chair of Truth has been set up as the light of the world, they have raised the throne of their abominable impiety, with the iniquitous design that when the Pastor has been struck, the sheep may be scattered.
Apart from the fact that it obviously talks about raising up some throne to displace or replace the Chair of Truth so as to strike the Pastor and scatter the sheep (undboutedly the Bogus Ordo "Popes") ... he's referring to that in the past tense, except that it hadn't happened yet. One would use this tense from the perspective of having seen a vision of the future when it had already happened.
He also calls out that the Chair of truth is the light of the world, indicating that he saw this light eclipsed by this impious counter-throne.
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