See, now this is just something I don't understand. It's something that happens often.
>What? You discovered a new revolutionary way to use power?
>Oh my god! We need to prevent this from ever spreading! No one should be allowed to know this! MC-kun, you have to be the only person ever to use this, or else!
And since they live in a dangerous world brimming with monsters trying to kill them, this makes even less sense.