'Stupid' is very subjective. Let’s take your example of the face masks. You (scientists including) call stupid whenever people aren’t wearing the masks. Others

'Stupid' is very subjective. Let’s take your example of the face masks. You (scientists including) call stupid whenever people aren’t wearing the masks. Others (also including scientists) might say that wearing a mask is stupid (because it’s weakening your immune system). Another example. If you’d be living in the Middle Ages and there would be a growing group believing the earth wasn’t flat, you’d be called stupid. Now, it’s the other way around. Either way, stupidity is very subjective when applied at an intellectual level. At a more practical level, stupid would be a child that just heard their parents say not to touch the furnace but still touches it and burns itself. One could call it stupid, but it’s also a way of learning, exploring and getting experience. So even at this level, 'stupid' is subjective