For me, this word "Stupidity" is better to replace with the sentence "Lack of knowledge about something",
this make things better when u think they actually just need to have knowledge about something so that they wont cause mistake and commit a wrong path

However, there are also cases where stupidity had become arrogant and one does not able to realize mistake at all.
In this case we can say that,
the person who is known as stupid for another person has their own thinking, own reason to commit something, which they may or may not have the total reason to ensure that their doing can cause the proper result, but it is a wrongful behaviour for those because of not knowing what that person's reason to do commit that action.
Or that person is a totally arrogant case, even he himself think he may result in the wrongful result, he still insist on it.
This is one no-solving-matter due to the stubbornness of him