Most users probably don't assume anything, it doesn't even enter the lists of concerns or cares they have or ever would. It's not that they don't understand the subject, they simply do not give a crap one way or the other.
Random family in the US or elsewhere simply does not give a crap about things like this, no matter how much you want them to.
It's not ignorance, and the most intellectually dishonest arguments are really the argument here - "If people knew more about the subject or could know more, they'd care!".
If they knew as much as you did, they still wouldn't care.