I'm not a very big fan of the Harry Potter franchise, and even though I've seen every movie I don't plan on reading any of the books, so I'm left with many questions that may or may not be explained in the books.
There's one main question that has bothered me since the first film- why do the Hogwarts crew care so much about staying hidden from Muggles?
Apparently I'm not the only one who wonders why wizards care so much about Muggles, and illustrator George Rottkamp and Dorkly's Andrew Bridgman created this comic that colorfully illustrates why wizards should stop hiding and start healing!
-Via Dorkly
Sure, they could try to have a shield up at all times to guard against knives in the back and bullets from a distance, but that would be rather draining... and the first time a wizard "murders" an entire mob of angry anti-magic activists that got too close and threatening, it'll justify further anti-magic thinking throughout the general public, regardless of how many cancers some wizards cure.
Worst case scenario if wizards go around murdering anyone who openly persecutes them, which the comic clearly advocates, government agencies could step in on the side of the anti-magic majority, at which point the wizards not only have to shield themselves and their homes against knives and bullets, they have to shield against drone strikes and missile strikes...
It seems to me like a few memory wipes here and there and generally hiding would be much easier. Certainly easier than trying to form a one-world government that subjugates all of humanity under the vicious rule of a pack of vengeful wizards that will smite anyone who dares speak up against them. Including their own. Hermione, and those like her, would probably try to start a revolution, but they'd likely be wiped out. The whole regime sounds an awful lot like how Voldemort and crew operated...
At which point, you have to wonder if any "cancer curing" wizards would be around in any significant number. Voldemort didn't seem like the "cancer curing" type, but he definitely seemed like the "rule the world with a fiery fist" type.