About what?
This information and hygienic is not even practiced among the people who thinks they're more civilized than other.
Knowing about it and practicing it, are two different things.
I know smoking is bad for me, for example, but I still smoke.
I'll not go to iron era, just go back to.middle ages and read about your ancestors hygiene.
In the middle ages, it was known that staying away from sick people prevents you from becoming sick as well. This is why quarantine and containment are about the oldest forms of fighting against epidemics known to man.
You act as if medieval people were still flinging fecies at eachother and didn't know anything about anything.
You're simply wrong. There's nothing "revolutionary" in your prefered scripture in that sense.
Or quicky read statics in the whole world about percentage of people washing their hands before eating and after using toilets.
Again, there's a difference between
knowing about it and actually
practicing it.
Take random guy that leaves a public restroom. Ask him if he washed his hands. If he says "no", ask him if he understands why it's important to wash hands. I'll bet you a million dollars that that person will know exactly why it is important to do so - eventhough he didn't do it.
Your entire premise is incorrect and short sighted.