That really is probably the best response I could imagine. Hopefully it doesn't sail over the OP's head.

Also:
"...because they all think of chicken pox, measles, and whooping cough as negligible trifles."

Forgetting, of course, how many people died of these negligible trifles, despite quarantine. And the number that could have died if not for quarantine is just unimaginable.

These diseases still exist and are still serious despite the frequency of mild cases. And the nild cases _are_ frequent, thanks to vaccines and antibiotics and antivirals.