"Well, remember how I said the Ministry controls the only newspaper? That is pretty much the reason why they can get away with it. The Ministry maintains a thin veneer of democracy on behalf of the Muggleborn and Half-Bloods. The thing about democracy though is that so long as you can maintain 51% of the vote, you can do whatever you'd like, and due to the way people think in general, being the most popular candidate means that about a third of people are going to like you no matter what, a third are going to hate you, and the remaining third is going to be undecided. And that undecided third is going to make up their mind based on what you do, which they'll learn about in the newspaper. Which the Ministry controls. The result is that they can legalize a significant amount of corruption, and by keeping the populace cripplingly misinformed and weak they have no reason to fear for their job security while doing so."