Why were people with diseases asked to live outside the camp?

It doesn’t seem fair. The ones who lived outside the camp faced great difficulties, since they were completely cut off from society (except for supplies left behind). Yet everyone understood the measure as an unpleasant but necessary way to prevent God’s dwelling from being defiled (Numbers 5:1-4). On the positive side, these harsh requirements served to protect the unclean person, keeping the holy things at a distance so no one would die for accidentally touching them. These rules also protected the rest of the camp, quarantining the disease and preventing its spread. No exceptions were made–even Moses' sister Miriam was exiled.