I wasn't at all sure what you meant. The emphasis in your comment could very easily have been on "We" (another hominid discovered how to harness fire, which seems to be your intent) or on "invent" (fire happens in nature, hominids didn't invent it at all). The latter is perfectly in line with the kind of "attempting to be clever but actually just annoying" pedantry that nerdy internet spaces often see.
I think he's just saying "We didn't start the fire (It was always burnin' since the world's been turnin'.)".
The writings of St. John Climacus were also far more useful and interesting to people at the time since they dealt with what for them were practical matters of how to lead the life of their community. This isn’t because they were narrow-mindlessly religious. Monks also had to busy themselves with calendrical calculations — and therefore astronomy. These were works of what we would call practical philosophy or ethics, like the famous Meditations of Marcus Aurelius. It would also have been tragic to potentially lose those culturally significant writings in favor of astronomical or mathematical texts.
All of this is valuable, both the cultural knowledge and the scientific. I doubt the monks realized the gravity of their choice so long ago.