She was still a carrier of the disease and infected others by her negligence.
Yes, they are silly, stupid, and a danger to the rest of us. If I could be assured that these idiots would only be harming themselves, I would not be as concerned. But, by their arrogance and stupidity, they put me and my loved ones in danger when there is no need for them to be so. THAT is inexcusable.
Sigh. There is a sense in which the last 100 years of having antibiotics and vaccines have made us forget the dangers of diseases. We have become complacent. We have *lived* in a protective bubble for the last century or so. Well, the bubble has burst. We cannot be complacent about this type of thing any longer.
Before about 100 years ago, epidemics were fairly common. Quarantines of *apparently* healthy people was normal and understood to be necessary for the health of everyone. This debate would have been considered a form of insanity 150 years ago. it would have been obvious to everyone that quarantines were required.