yeah, it's seem kinda obvious how forceful it's presented, i would like to know why, maybe it's about natural law or something knowing what Sensei like.
I vaguely remember in early chapters something about magic and nature being connected. Perhaps too much magic negatively affects nature. Who knows, maybe Araneum is an isolated wasteland caused by excessive high power magic
This is why Senshi from Dungeon Meshi resents magic. At least for non-magic user, the "convenience" that magic bring, if it's too much and often, can dull their skills
If Ida here is a good example of how the Association views magic, i.e. "Use it for everything" that probably explains why sensei isn't interested in joining. He seems to be in the "don't use magic as a crutch" camp.
I was thinking something similar except replace magic philosophy with like, boundaries and manners, and "don't use magic as a crutch," with, "don't show up at my fuckin' house unannounced and uninvited."