The answerer does say that either the perfect past (Latin’s closest to -ed) or the pluperfect past (Latin’s closest to had -ed) would work, they just chose perf

The answerer does say that either the perfect past (Latin’s closest to -ed) or the pluperfect past (Latin’s closest to had -ed) would work, they just chose perfect past. Maybe that choice was because the perfect past has a sense of finality that English’s simple past doesn’t, so it isn’t necessary to reach deeper into the sequence of tenses as it is in English.