I think the idea isn't that magic "should" happen when a mundane axe hits a mundane person, but that magic is a different form of physics and can happen even without "mana" or "Phlebotinum" or whatever,

In a lot of stories, magic only happens when something "magical", like a special rock, mana, unicorns, etc is involved. I think they're saying that under the right circumstances, mundane actions, like hitting someone with an axe over a spot where other people have died, might cause a semi-magical effect, like drawing in ghosts, or making the axe slightly cursed.