Because they were trained to think it was their duty as citizens.
Where and when were they trained? Mencken answered that in 1927.
"And what is a good citizen? Simply one who never says, does or think anything that is unusual. Schools are maintained in order to bring this uniformity up to the highest possible point. A school is a hopper into which children are heaved while they are still young and tender; therein they are pressed into certain standard shapes and covered from head to heels with official rubber-stamps."
-- H.L. Mencken, Prejudices: Sixth Series, 1927
As plague hysteria begins spreading across headlines around the world, there is one detail almost nobody is talking about: governments and military biodefense programs have already poured major resources into developing dozens of plague vaccines.
More than 21 plague-vaccine candidates are under development, spanning mRNA, self-amplifying RNA, recombinant protein, viral-vector, live-attenuated and other technologies.
--- Nicholas Hulscher