It is backwards. It’s rather often that, as an adult, I learn something that is fundamentally contradictory to what I learned in grade school. Usually it’s the framing of events, details that got left out… They paint a story that usually ends with the US saving the day somewhere. Kids learn more politically accurate stories from their family members. Teachers will shush down a kiddo who speaks up on these details, because “professionalism” means yielding to the potential that any one of their student parents might not find the alternative material acceptable.

Whoooo doggy! That's a question with an answer that depends on several variables.

I guess you can lead with, "I understand how you can think that, but it really isn't, it's just something that isn't taught in ____ schools."

If they show interest and time is short, you can explain it was once taught at certain levels, but this society stopped teaching it because they focused on business interests and profit motive? And discuss as much as you can in simple terms, and pick up again at the next opportunity.

If time is long, then I would say follow the same line but I hope you have patience to correct a lot of disinformed perceptions and answer questions.

But also be aware that ignorance very often leads to arrogant disinterest. As much as I want to make people interested, it's a fool's errand. That doesn't mean we can't or shouldn't put forth the effort, but it means if your energy and time are better spent following another avenue, then maybe you consider that.