The entire population is already at risk, sweetheart. This Quarantine isn't going to do a thing but make the rest of us sick in our plastic little bubble. You do now how the spread of infectious diseases works, right? This isn't about keeping us or the rest of the wizarding world safe, it's the fact they're all too stupid and fearful to figure out how to handle the situation, and imprisonment seems like the best option.
And I see, resorting to house prejudices, hm? That's so very mature of someone who claims to be 'Head Girl'.