Its just a word people use when they don't understand what you are doing or something is about.
A more accurate way to say it is "They are ignorant about what you are doing."
This can pertain to the most intelligent of people.
I just blow them off. If they don't ask, they are choosing to remain ignorant.
Let them keep there opinions. Down the road it will come back to haunt them or they will look like a ideate at one point and thats worse than being called stupid.