It's not really your magic if someone has to give it to you. And then they'd turn it on you in an instant if they wanted.

[ Which is his problem. If someone who always had magic mentioned it the people here might turn against them too. It wasn't just the magic the monarchs gave them-- it was all of them. And he didn't really want to sort through with that. Magic didn't always help. It solved plenty for wizards, sure, but they also didn't war as much as Muggles did. If muggles had magic on hand when they were fighting, well... That didn't seem like it would go too well. ]

Or it could make it worse. If everyone here had magic and decided to blow up half the castle then loads more people would be in trouble.