@ShinGetsu
Yes ... and no as well. If you go to reread the chapters that preceded Leilei getting her sage degree ( like I did just now, to be sure I was not talking nonsense ), Rory view of what to limit is plainly explained. See, Rory has no issue with people of Alnus using guns, but she was throwing daggers to Leilei speaking about revealing the existance of gunpowder ( to the point Itami got cold sweats thinking that Rory was thinking on killing Leilei on the spot ) ... while not having a issue with Leilei work on multiple layer detonation spells. Also , she was EXTREMELY interested in that elf scholar theory of heliocentrism and in the popular reception of it ( getting Itami to get cold sweats again ) ( P.S BTW that elf report to the sage academy is pertinent to this chapter events. Glad I reread it ).
In other words, Rory has no issues with
tecnological steps, since, if she did , she would object to Leilei use of detonation magic that clearly mimics the gunpowder usage ... who cares if your grenade is powered by magic or by a chemical reaction if it explodes the same way ? But she really dislikes the spread of ideas she consider to be alien or out of time: she clearly thinks their world is not ready for heliocentrism and definitely does not want the idea of chemical reactions creating explosions being known in Alnus ( again no issue with usage of guns ... and this is not even a exception for Itami entourage, since we already seen werewolves in tactical gear and with guns in hand ). If technological spread was what Rory was worried about, she would not care about heliocentrism and she would be mad with dark elves wearing bazookas or werewolves in tactical gear. But we see the opposite ...
Her dislike of heliocentrism is what makes me think that she should be very unhappy with Leilei knowing General Relativity. If you think about it, heliocentrism is even far more useless in technological terms than General relativity ( I mean, General relativity has uses in our everyday life ( GPS, for a quick example ) but heliocentrism ... does not ) ... Besides that, General Relativity, while not needing heliocentrism, definitely implies, as this chapter points out by itself, the idea of heliocentrism ... and Rory does not like that