No, not stupid, just uninformed. You could call it ignorant, but that sounds insulting. There are many things in the world I am uninformed about, therefore ignorant. Before I kept chickens I don't think I really gave much thought as to how many eggs a hen could lay in one day. Having watched many Merrie Melody cartoons where the chickens sing & dance & lay lots of eggs at once I might have said 6 or 12 myself.
I'm now part of a local Poultry Fanciers' Association that mans the Poultry Tent at our county Fair. I really enjoy spending time there answering visitors' questions about chickens. There really are a lot of folks who think a hen can lay more than one egg a day, and I like to inform them about what a miraculous & complicated process it is for a bird to produce each egg. They go away with lots more respect for chickens, and the eggs they have to eat.
Sometimes I'll stand in front of the dairy case with my kids and point to allllll the dozens & dozens of eggs in cartons there. "Just think" I tell them "that's a whole day's work for hundreds of individual hens!"